Mengfan Zhou, Steffen Frensch, Vincenzo Liso et al.

Energies • 2022

In this paper, the performance of a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) was modeled using literature data. The paper attempted to combine different sources from the literature to find trends in the degradation mechanisms of HT-PEMFCs. The model focused on the activation and ohmic losses. The activation losses were defined as a function of both Pt agglomeration and loss of catalyst material. The simulations revealed that the loss of electrochemical active surface area (ECSA) was a major contributor to the total voltage loss. The ohmic losses were defined as a function of changes of acid doping level in time. The loss of conductivity increased significantly on a percentage basis over time, but its impact on the overall voltage degradation was fairly low. It was found that the evaporation of phosphoric acid caused the ohmic overpotential to increase, especially at temperatures above 180 °C. Therefore, higher temperatures can lead to shorter lifetimes but increase the average power output over the lifetime of the fuel cell owing to a higher performance at higher temperatures. The lifetime prognosis was also made at different operating temperatures. It was shown that while the fuel cell performance increased linearly with increasing temperature at the beginning of its life, the voltage decay rate increased exponentially with an increasing temperature. Based on an analysis of the voltage decay rate and lifetime prognosis, the operating temperature range between 160 °C and 170 °C could be said to be optimal, as there was a significant increase in performance compared to lower operating temperatures without too much penalty in terms of lifetime.

Sandhya Prakash, Samsudeen Naina Mohamed, Kalaichelvi Ponnusamy

Water and Environment Journal • 2024

Abstract This study aims to improve the performance of microbial desalination cell (MDC) using Vigna mungo (Black gram) wash water, reported for the first time as an anolyte utilizing a graphite plate and carbon brush as the anode. Power generation was facilitated by the exoelectrogen, Shewanella putrefaciens MTCC 8104. Polarization studies revealed that the graphite plate MDC attained a high power density of 2720 ± 50 μW/m 2 compared to carbon brush for two electrode pairs. The COD removal and desalination efficiency were better for carbon brush MDC, achieving 58.17 ± 2% and 38.14 ± 2% removal, respectively. Power production can be enhanced by increasing the cathode's ability to accept the electrons, reducing the ageing of biofilm and promoting complete oxidation of the substrates. Upon improving its performance, MDC can act as a sustainable technology, collaborating with industries seeking solutions for wastewater treatment, energy generation and agricultural sectors on a large scale.

Hongzhi Ma, Cheng Peng, Yan Jia et al.

Royal Society Open Science • 2018

A single-chamber microbial fuel cell (MFC) was used in this study to treat recycled stillage obtained from food waste ethanol fermentation. Corresponding substrates inside the system were evaluated by fluorescence spectra, and microbial communities were also investigated. Results demonstrated that output voltage and current, respectively, reached 0.29 V and 1.4 mA with an external resistance of 200 Ω. Corresponding total organic carbon and chemical oxygen demand removal efficiency reached more than 50% and 70%, respectively. Results of fluorescence spectra demonstrated that tryptophan-like aromatic, soluble microbial by-product-like and humic acid-like substances accumulated and were not easily degraded. Microbial community analysis by high-throughput sequence indicated that Advenella and Moheibacter occupied the highest proportion among all genera at the anode instead of Geobacter . These results may be due to complicated accumulated stillage, and potential tetracyclines possibly influenced microbial communities. Details on how stillage affects MFC operation should be further studied, and a solution on relieving effects should be established.

Anam Asghar, Addin Salihoudin, Abdul Aziz Abdul Raman et al.

Environmental Progress & Sustainable Energy • 2016

Microbial fuel cell (MFC) is a sustainable and energy efficient technology, which uses graphite as cathode for hydrogen peroxide (H 2 O 2 ) production often with simultaneous power production. Nevertheless, slow kinetics of oxygen reduction reaction (ORR) at the surface of graphite often results in poor performance of MFC. In an attempt to improve the performance of MFC for in‐situ H 2 O 2 production, a treatment of graphite cathode using nitric acid was performed. The treatment was conducted in three steps (i) heat treatment at 450°C for 2 h; (ii) acid treatment with concentrated nitric acid for 5 h; and (iii) drying at 120°C for 2 h. After the treatment, four times increase in surface area of treated cathode (GR‐HA) was observed. Energy‐dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared (FTIR) analysis revealed the presence of nitrogen and quinone based functional groups on the surface of GR‐HA. Cyclic voltammetric (CV) analysis of GR‐HA cathode further confirmed the production of H 2 O 2 at the peak current value of −3.7 mA and on‐set potential of −0.1 V. Following CV analysis, H 2 O 2 production experiments were performed in a dual chamber MFC using GR‐HA as cathode. Maximum 150 mg/L of H 2 O 2 was produced with simultaneous power production of 36.438 mW/m 2 . Approximately, 25% increase in both H 2 O 2 and power production was observed in the case of G cathode. Subsequently, Fenton oxidation experiments were performed (with GR‐HA and GR‐CA cathodes) to determine the efficacy of in‐situ produced H 2 O 2 . This resulted in an increase of 8.28%, 11.04%, and 31.32% in decolorization, chemical oxygen demand (COD), and Total Organic Carbon (TOC) removal efficiency, respectively. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 382–393, 2017

Partha P. Mukherjee, Chao-Yang Wang

ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology • 2007

It is widely recognized that the performance degradation and the limiting current behavior in polymer electrolyte fuel cells (PEFC) are mainly attributed to the excessive build up of liquid water in the cathode side and the resulting flooding phenomena. Liquid water blocks the open pore space in the catalyst layer (CL) and the gas diffusion layer (GDL) leading to hindered oxygen transport and covers the electrochemically active sites in the CL thereby rendering reduced catalytic activity. The CL flooding therefore plays a crucial role in the overall PEFC performance limitation. In order to elucidate the primary mechanisms of liquid water removal out of the CL, the factors affecting CL flooding and to discern the role and contribution of CL flooding on the overall PEFC voltage loss, a CL flooding model has been developed. The flooding model is based on a simplified structure-wettability representation of the PEFC CL and a physical description of water and heat balance along with electrochemical performance analysis. The model shows that the evaporation mechanism, depending upon the cell operating temperature and the GDL thermal conductivity, plays a crucial role in the CL flooding behavior and the cell performance.

Aswini Vellingiri, Young Eun Song, Ganapathiraman Munussami et al.

Journal of Chemical Technology & Biotechnology • 2018

Abstract BACKGROUND The c‐type cytochrome of the CymA of Shewanella oneidensis MR‐1 is essential for the anaerobic respiration of Shewanella sp . and transfers electrons from the inner membrane to various terminal electron acceptors, such as soluble redox shuttles and insoluble metal oxides. CymA is believed to be a passage to the outer membrane for dissipating the respiratory electron to the carbon electrode in a microbial fuel cell (MFC) with simultaneous electricity generation. While the deletion and heterologous expression of cymA in Escherichia coli have been studied, there are no reports of the overexpression and its effects on the corresponding bioelectrochemical performance in a MFC. RESULTS The cymA gene was overexpressed in Shewanella oneidensis MR‐1, and its upregulation was examined under aerobic, anaerobic, and MFC operating conditions by a reverse transcription‐polymerase chain reaction (RT‐PCR). Overexpression of the CymA protein was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). The MFCs inoculated with the engineered strains of MR‐1 achieved a higher maximum power of 0.13 mW and specific growth rate of 0.087 h −1 than those of the wild type MR‐1 (0.11 mW and 0.043 h −1 , respectively). The higher electrochemical activity of the mutant strains demonstrated by cyclic voltammetry and linear sweep voltammetry, indicates that more respiratory electrons can be transferred to the electrodes through overexpression of the cymA gene of MR‐1 in a MFC. CONCLUSION Overexpression of CymA improves the bioelectrochemical performance of MFCs. This suggests that metabolic engineering of a membrane‐associated redox protein, such as CymA, can further improve electricity generation of MFCs and produce an electrochemically enhanced bioprocess. © 2018 Society of Chemical Industry

Denis Bona, Dennis E. Curtin, Francesco Pedrazzo et al.

Journal of Fuel Cell Science and Technology • 2013

Carbon black based electrodes are generally recognized as state of the art for PEM fuel cell technology due to the high performance achieved with a relatively low Pt content. However, the catalyst carbon support is prone to carbon oxidation. This leads to a loss of the catalyst area and overall performance, along with a higher mass transport loss due to an increased flooding tendency. This phenomenon is particularly severe when the fuel cell experiences repetitive start-stop cycles. Therefore, specific countermeasures against catalyst layer carbon oxidation are required, especially for automotive and backup power applications, where the startup/shutdown rate is considerably high. The authors evaluated a basic design that uses a stack shunt. A properly modified control protocol, which includes the stack shunt, is able to avoid high cathode potential peaks, which are known to accelerate catalyst carbon support corrosion and its negative effects. During two separate durability tests, one adopting the shunt design and another using nonprotected shutdown, a 24-cell stack was subjected to continuous starts and stops for several months and its performance constantly monitored. The results show that when the shunt is used, there is a 37% reduction in the voltage degradation rate for each startup/shutdown cycle and a two-fold increase in the number of startup/shutdown cycles before an individual cell reached the specified “end of life” voltage criteria. Furthermore, ex situ FE-SEM analysis revealed cathode catalyst layer thinning, which is an indication that the emerging degradation mechanism is the catalyst support carbon corrosion, as expected. This provides further support that the constant voltage degradation rate typically experienced in PEMFCs can be primarily attributed to the catalyst support carbon corrosion rate. The proposed shunt protocol is very cost effective and does not require any substantial changes in the system. For this reason, its adoption is recommended as a viable method to decrease the catalyst support carbon corrosion rate and extend the operating life of the PEMFC stack.

Daniel F. Walczyk, Jaskaran S. Sangra

Journal of Fuel Cell Science and Technology • 2010

The feasibility of an alternative fuel cell architecture, called a ribbon membrane electrode assembly (MEA), is demonstrated for low-temperature polymer electrolyte membrane (PEM) fuel cells used in portable power applications by comparing it to a traditional bipolar “stack” architecture. A ribbon MEA consists of adjacent PEM cells sharing a common gas diffusion layer to allow for lateral electrical current flow and an integral gas-tight, conductive interconnect/seal, where adjacent cells meet to prevent reactant gas leakage. The resulting lateral arrangement of MEAs can be used to supply all MEAs simultaneously instead of individual bipolar plates with flow fields for a stack. A pair of two-cell ribbon MEAs, with and without an interconnect/seal, were designed, prototyped, and sealed by thermal pressing. The MEAs were clamped in a two-piece box fixture to provide reactant gases on the anode and cathode sides, hooked to a fuel cell (FC) test stand and yielded an open circuit voltage (OCV) of 1.43 V with an interconnect/seal and 0.6 V without. A two-cell bipolar stack PEMFC with identical MEA specifications had an OCV of 1.86 V. Polarization curves for the ribbon MEA with interconnect/seal showed the sensitivity of performance to clamping pressure and positioning of the copper current collectors. The ribbon MEA polarization curve was also shifted downward by 0.42 V as compared with that of the traditional stack, and suspected causes (e.g., gas leaking) are attributable to the nonoptimal test fixture design. Hence, the ribbon MEA architecture is shown to be feasible. Future work suggested includes improvements to the test fixture design, development of automated manufacturing capabilities for high volume production, and demonstration of a multicell (>2) ribbon MEA PEMFC design.

Anirban Roy, Frida Roenning, Douglas Aaron et al.

ECS Meeting Abstracts • 2020

Conventional research and diagnostic techniques for fuel cells and electrolyzers, such as polarization curves and EIS measurements, predominantly probe macroscopic performance characteristics. The works of Schuler, et al. [ 1 ] have given a detailed understanding of transport mechanisms inside a polymer electrolyte water electrolyzer (PEWE) by drawing extensively on such ex-situ techniques. However, these techniques cannot be used to probe in-situ behaviors of a PEWE. A need for reliable experimental data that captures in-situ spatial and temporal current distribution is the motivation for the segmented cell used here. Current distribution measurement in PEWEs was performed by Bender et al. [ 2 , 3 ] while Mench and coworkers pioneered the technique in similar flowing electrochemical systems [ 4 , 5 ]; a major innovation was inclusion of a printed-circuit board (PCB) with an array of shunt resistors attached to each segment as shown in Figure 1a. The advantage of this design is that, although the PCB and flow-field are segmented and electronically isolated, the other components of the cell are not. However, this design is subject to error since current can spread laterally through the porous transport layer (PTL) as it passes from the catalyst layer to the segmented flow field. Since activity at the catalyst layer is of great interest, understanding current spread is a critical step to utilizing current distribution measurements. This work focuses on characterizing the lateral current spread through PTLs. Work by Philips, Ulsh, and Bender [ 3 ], showed that the experimental setup could be modified with the help of masks to characterize lateral current spread through the PTL. A set of experiments was thus designed to investigate current spread through the porous transport layer both “inward” and “outward” from a flow field segment. The goal of these experiments is to quantify current spread, allowing correction of its contribution to obfuscating measurement of current generated in the catalyst layer. High current was detected for the PCB segment corresponding to the unmasked area as expected, but substantial current was measured around the exposed area, as well (Figure 1b). If there was zero outward current spread, no current would be measured anywhere away from the single segment area generating current. Figure 1c shows average current density as a function of radial distance from a generating spot; Figure 1d plots normalized current density as a function of radial distance. This set provides calibration for how much current spread laterally outwards as detected at points located away from a current-generating area. Similarly, inward contributions were also mapped. These experiments were also carried out for two types of PTL – Ti-foil-based thin LGDLs [ 6 ] and Ti-based felt PTLs. Preliminary observations indicate that lateral current spread in the Ti-felt-based LGDLs is less than that of the Ti-based foil LGDLs. This work quantifies the lateral current spread seen inside a LGDL and also lays the groundwork to correct current spread recorded in a spatially-resolved current distribution measurement technique. It is part of DOE project #DE-EE0008426 "Developing novel electrodes with ultralow catalyst loading for high-efficiency hydrogen production in proton exchange membrane electrolyzer cells." References Schuler, T., T.J. Schmidt, and F.N. Büchi, Polymer Electrolyte Water Electrolysis: Correlating Performance and Porous Transport Layer Structure: Part II. Electrochemical Performance Analysis. Journal of The Electrochemical Society, 2019. 166 (10): p. F555-F565. Reshetenko, T.V., et al., A segmented cell approach for studying the effects of serpentine flow field parameters on PEMFC current distribution. Electrochimica Acta, 2013. 88 : p. 571-579. Phillips, A., et al., Utilizing a Segmented Fuel Cell to Study the Effects of Electrode Coating Irregularities on PEM Fuel Cell Initial Performance. Fuel Cells, 2017. 17 (3): p. 288-298. Clement, J.T., D.S. Aaron, and M.M. Mench, In Situ Localized Current Distribution Measurements in All-Vanadium Redox Flow Batteries. Journal of The Electrochemical Society, 2015. 163 (1): p. A5220-A5228. Ertugrul, T.Y., et al., In-situ current distribution and mass transport analysis via strip cell architecture for a vanadium redox flow battery. Journal of Power Sources, 2019. 437 : p. 226920. Mo, J., et al., Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting. Science Advances, 2016. 2 (11): p. e1600690. Figure 1

Denise A. McKahn, Xizhu Zhao

ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology • 2012

Numerous applications exist requiring power for small loads (<5W) with minimal mass operating in extreme ambient conditions. Making progress toward reducing stack mass, we investigate the influence of flow field channel depth and endplate compression on cell performance. The best performance was found at endplate compressions of 139 psi, cathode channel depths of 0.032 in and anode channel depths of 0.032 in. The maximum power mass-density achieved with these 4.84 cm2 cells was 16.8 mW/g in a single cell stack. If deployed in a multicell stack, this same performance would translate to a power mass-density of 45.3 mW/g, nearing the performance of off-the-shelf lithium ion batteries (approximately 70 mW/g).

Koichi Matsutani, Katsuichiro Hayakawa, Tomoyuki Tada

Platinum Metals Review • 2010

To investigate the effect of load cycling, platinum (Pt) and platinum-cobalt (PtCo) fuel cell catalysts with different particle sizes were prepared and evaluated for their durability against load cycling. The particle size of the Pt and PtCo catalysts was controlled by changing the catalyst loading and by applying heat treatment. Pt catalysts with particle sizes of 2–3 nm and 4–5 nm and PtCo catalysts with sizes of 3–4 nm, 4–5 nm and 7–8 nm were obtained. A potential sweep from 0.65 V to 1.05 V was applied to the cathode of membrane electrode assemblies (MEAs) prepared with these catalysts,and the degradation of their mass activity and cell voltage were evaluated. As a result of this investigation, it was found that Pt catalysts with particle sizes of 4–5 nm and PtCo catalysts of particle sizes 7–8 nm showed better stability against potential sweep, with the Pt catalysts of sizes 4–5 nm showing the best stability of all the catalysts tested.

E. L. Thompson, W. Gu, H. A. Gasteiger

Handbook of Fuel Cells • 2010

Abstract This article discusses recent performance studies of PEM (proton exchange membrane) fuel cells operating at subfreezing temperatures. The major sources of voltage loss (kinetic, ohmic, and transport) are experimentally isolated to quantify their contribution to the total voltage loss. Thus, the oxygen reduction reaction (ORR) kinetics and membrane proton conduction resistances are quantified at subfreezing temperatures. To provide a mechanistic explanation for the observed temperature and water‐content dependency of proton conductivity, phase transitions and state of absorbed water in Nafion ® was measured using differential scanning calorimetry. While it is reasonably well known that a successful PEM fuel cell cold start strongly depends upon the effective use of membrane and electrode to store product water (ice) until the cell temperature reaches 0 °C, the exact water (or charge) storage capacity of the membrane and the cathode electrode as well as the estimated water partitioning into these two locations as a function of operating conditions has not been discussed in detail and is presented here. In addition, cryo‐SEM is used to examine ice formation in the electrode and confirm the above estimates. The electron proton conduction resistance was used to predict the ORR current distribution within the cathode electrode, which provides insight into how ice filling proceeds in the electrode, and is supported by cryo‐SEM findings. Finally, the measured and estimated voltage losses are summarized to highlight the contribution of the various voltage loss terms on the overall initial voltage loss during operation at −20 °C, for a wide range of membrane water contents and current densities.

Lisa Utami, Lazulva Lazulva, Yuni Fatisa

Indonesian Journal of Chemical Science and Technology (IJCST) • 2020

This study aims to study how the potential of peat water as a source of electrical energy using Microbial Fuel Cell (MFC) technology. Observations were made on two chamber vessel reactors (anodes and cathodes) and connected to electrochemical cell circuits (voltaic cells) and voltage values were measured, current, power density generated from the circuit for 9 days.The results of the measurement of the maximum voltage value, the maximum current generated and the maximum power density (8th day) of the reactor are obtained as follows: 50.8 mV, 1 µA and 3.64 x 10-2 mW / m2

Somil Thakur, Bhaskar Das

Nature Environment and Pollution Technology • 2021

Microbial fuel cells (MFC) have gained focus due to their diversity in operating conditions & substrates for the generation of sustainable green energy. In the present study, novel MFC has been fabricated using the recyclable aluminum can as air-cathode and graphite rod as anode for the treatment of domestic wastewater and simultaneous power generation. Three different substrate (COD) concentrations, high (>800 mg.L-1), medium (250 mg.L-1 - 800 mg.L-1) and low (<250 mg.L-1) were used. The maximum COD removal efficiencies, voltage generation, power densities were found to be 80%, 0.71 V, and 304.46 mW.m-2 respectively in high strength wastewater setup. In both medium and low strength wastewater setups, after 288 hours, the COD was reduced below 50 mg.L-1 thus limiting the electricity generation substantially. Setup with low-strength wastewater produced a maximum CE (%) of 13.80. Overall results showed that although high-strength wastewater produced better and maximum power densities, medium and low-strength wastewater setups were more consistent in energy generation throughout the experiment.

Nurul Atiqah Shamsuddin, Muhammad Najib Ikmal Mohd Sabri, Husnul Azan Tajarudin et al.

IOP Conference Series: Earth and Environmental Science • 2021

Abstract Microbial Fuel Cell (MFC) is gaining high interest by researcher around the globe as this is a promising renewable technology that has capability in producing electrical energy. In this study, the effect of the thermal pretreatment method (60, 80, 100, 120 and 140°C) on dewatered sludge (DS) as substrate for electrogenic bacteria (EB) in ML-MFC was optimized using one-factor-at-a-time (OFAT) method. The treated sludge then was used in ML-MFC by exposing them to the constant incubation temperature (35°C) with constant parameter of pH (6), initial moisture content (30 % vol/wt) and electrodes distance (3 cm) for 7 days incubation period. The performance of ML-MFC was relied on generation of soluble chemical oxygen demand (SCOD), power generation and EB biomass. Results shows the thermal pretreatment at 80°C was the optimum condition as the DS degradation rate (increment 78 %) when DS was treated for 4 h time treatment prior used in the ML-MFC. The degradation of DS was further degraded in ML-MFC via bio-catalysis process (51 % of SCOD produced compared initial DS inserted in MFCs ∼ 66 % SCOD removal). It was important to have a high DS degradation as the EB in ML-MFC would obtain more ‘food’ to growth thus increased the voltage (239 mV) and power density (98.34 mW/m 2 ) generation. In comparison, the control ML-MFC recorded low performance of DS degradation rate (21 %), voltage (24 mV) and power density 0.88 mW/m 2 . Thus, by combining the pretreatment method of dewatered sludge prior used in ML-MFC it could improve the performance and expanding the application of ML-MFC as future renewable technology for sustainability of power sources. The EB strains was Bacillus subtilis sp .

Parvaiz Ahmad Dar, Wan Zaireen Nisa Yahya, Azmat Ali Khan et al.

Macromolecular Symposia • 2025

Abstract Microbial fuel cells are utilized in electromicrobiology for the purpose of cleaning wastewater and producing electricity. Anaerobically, MFCs use microbial catalysis in the anodic compartment to transform the chemical energy stored in organic and inorganic molecular bonds. Using the soil sample, four exoelectrogens are isolated. Each of the four single‐chambered mediator‐less microbial fuel cell design are used to inject the extracted soil exoelectrogens. A nutritional medium is used to operate the reactors in batches of 15 days. The exoelectrogen ISO4 ( Bacillus amyloliquefaciens strain NSB4), followed by ISO3 (cereus strain BXC6), ISO2 ( Bacillus sp. (in: Bacteria) strain 4N), and ISO1 ( Staphylococcus argenteus strain D7) achieve the best growth rates. On average, data on energy generation shows that MFCs with ISO4 have the maximum voltage and power density at 1024 mV external resistance (1 kΩ), followed by ISO3 at 609 mV, ISO2 at 560 mV, and ISO1 at 487 mV. Power densities of isolates are recorded as: 41.281 mW/m 2 , 29.241, 12.723, and 3.552 mW/m 2 for ISO4, ISO3, ISO2, and ISO1, respectively. The research finds that the energy output of MFC reactors is affected by the exoelectrogen substrates. Cyclic voltammetry (CV) experiment demonstrates that exoelectrogens directly transport electrons to the anode surface via cytochromes and other substances associated with the cell membrane. It has been previously difficult to produce power from pure isolates, but new research reveals that this is no longer an issue. Pure cultures of exolectrogens use to generate current also show a broad substrate utilization spectrum, in line with previous studies.

Xiaoou Wang, Yu Zhang, Changping Zhang et al.

Sustainability • 2023

Constructed wetland–microbial fuel cell coupling systems (CW–MFCs) have received significant academic interest in the last decade mainly due to the promotion of MFCs in relation to pollutants’ degradation in CWs. Firstly, we investigated the effect of hydraulic retention time (HRT) and electrode configuration on the flow field characteristics of CW–MFCs using graphite rods and plates as electrodes, as well as the optimization of electrode configuration using computational fluid dynamics (CFD) numerical simulation. The results showed that: (1) the apparent HRT was the most influential and decisive factor, with a contribution of over 90% for the average HRT of CW–MFCs; (2) anode spacing was the most influential factor for the hydraulic performance of CW–MFCs, with contributions of over 50% for water flow divergence and hydraulic efficiency (λ) and over 45% for effective volume ratio (e); (3) anode size was significant for e and λ, with a contribution of over 20%; (4) cathode position and cathode size had no statistically significant effect on the hydraulic performance of CW–MFCs. It was mainly through the blocking of water flows, flows around, compressing water flow channels and boundary layer separation that the MFC electrodes influenced the hydraulic characteristics of the flow field in CW–MFCs. Optimizing the flow field by optimizing the electrode configuration helped to facilitate electricity generation and pollutants’ removal in CW–MFCs. This study offers a scientific reference for improving the hydraulic performance of CW–MFCs, and it also provides a new research perspective for improving the wastewater treatment and electricity production performance of CW–MFCs.

Mark Breheny, Kyle Bowman, Nasim Farahmand et al.

Journal of Chemical Technology & Biotechnology • 2019

Abstract Microbial fuel cells (MFCs) produce electricity as a result of the microbial metabolism of organic substrates, hence they represent a sustainable approach for energy production and waste treatment. If the technology is to be implemented in industry, low cost and sustainable bioelectrodes must be developed to increase power output, increase waste treatment capacity, and improve service intervals. Although the current application of abiotic electrode catalysts, such as platinum and electrode binders such as Nafion leads to greater MFC performance, their use is cost prohibitive. Novel bioelectrodes which use cost effective and sustainable materials are being developed. These electrodes are developed with the intention to reduce start‐up time, reduce costs, extend life‐span and improve core MFC performance metrics (i.e. power density, current density, chemical oxygen demand (COD) reduction and Coulombic efficiency (CE)). Comparison of different MFC systems is not an easy task. This is due to variations in MFC design, construction, operation, and different inocula (in the case of mixed‐culture MFCs). This high intra‐system variability should be considered when assessing MFC data, operation and performance. This review article examines the major issues surrounding bioanode and biocathode improvement in different MFC systems, with the ultimate goal of streamlining and standardising improvement processes. © 2018 Society of Chemical Industry

Ru-Jun Yu, Guang-Yi Cao, Xiu-Qing Liu et al.

Journal of Fuel Cell Science and Technology • 2006

The support tubular proton exchange membranes (STPEMs) were fabricated successfully by impregnating porous silica pipe into a solution of perfluorinated resin. The structures of the inner, outer, and cross section of support PEM tube were characterized intensively by scanning electron microscopy observation. In addition, the conductivity and impermeability were measured by electrochemical impedance spectroscopy (EIS) and the bubble method, respectively. Results show that the conductivity of the PEM can reach as low as 1.46S∕m when using the silica pipe of 0.7mm wall thickness. Subsequently, the ST membrane electrode assembly for direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC) applications was prepared first by loading Pt∕C and Pt–Ru∕C catalyst ink onto the outer and inner surfaces of the PEM tube, respectively. The performances of the tubular DMFC and the PEMFC were tested on a self-made apparatus, which shows that the power density of tubular DMFC can reach 10mWcm−2 when 4molL−1 methanol solution flows through the anode at 80°C, and that the power density of tubular PEMFC can reach up to 60mWcm−2 when hydrogen flows at the rates of 20mlmin−1 through the anode at 60°C, both the cathodes adopting air-breathing mode.

S. Foresti, G. Manzolini

Fuel Cells • 2018

Abstract An innovative micro‐cogeneration system (m‐CHP) based on membrane reformer and polymer electrolyte membrane fuel cell (PEMFC) is developed within the FluidCELL project. The purity of the hydrogen separated by the membrane reformer can decrease over time, due to membrane/sealing degradation, therefore a methanator is adopted to prevent CO poisoning of the fuel cell. This paper investigates the optimal control strategies of a polymer electrolyte membrane (PEM) fuel cell at different hydrogen purities by using a detailed 1D model, including the CO poisoning on the anode Pt‐Ru catalyst, and calibrated against experimental data. Simulation results show that the system is able to work also with low‐purity hydrogen thanks to the effectiveness of the methanator, the resistance to CO poisoning of the Pt‐Ru anode catalyst, the small voltage drop due to inert gases accumulation in the anode recirculation loop: at 0.3 A cm −2 as current density, the stack efficiency is always above 60% even when the membranes selectivity drops to 5 10 2 .

Gholam Reza Molaeimanesh, Masoud Dahmardeh

Fuel Cells • 2021

Abstract One of the parameters which can greatly affect (i.e., enhances or diminishes) the performance of a PEM fuel cell cathode is the GDL microstructure. In the present study, the role of carbon cloth GDL microstructure on the performance of a PEM fuel cell cathode is investigated, for the first time. In this regard, three carbon cloth GDLs with three different microstructures are reconstructed via merging bundles of carbon fibers with sinusoidal form; afterward, the passing reactive air through these GDLs is simulated at pore‐scale using lattice Boltzmann approach. The distributions of oxygen and water vapor through the carbon cloths and the distribution of current density on the catalyst layers are presented and analyzed. The results show that when the carbon cloth bundles consist of more fibers (i.e., having larger cross‐sections), the penetration of oxygen toward the catalyst layer is more difficult, and consequently, the average current density is smaller. Besides, the results reveal that the through‐plane compactness of carbon cloth microstructure does not bring a significant effect on the distribution of current density and species.

Agus Pulung Sasmito, Tariq Shamim, Erik Birgersson et al.

ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology • 2013

Portable and motive applications of open-cathode polymer electrolyte fuel cells (PEFCs) require not only good stack performance but also a light and compact design. In this context, we explore how edge cooling with three different fin designs — one standard rectangular fin and two triangular fins that essentially halve the size of the fins — can improve the thermal and water envelopes inside the stack as well as stack performance whilst reducing the overall volume. The results suggest that all three edge-cooling designs give rise to lower and more uniform local temperature distributions as well as higher and more uniform hydration levels at the membrane in the stack compared to the conventional open-cathode PEFC without fins and design with additional air coolant plates. In addition, edge cooling design with one of the triangular fins yields the best performance (around 5% higher in term of power per unit catalyst area and power per unit weight; and ∼10% higher in term of power per unit volume as compared to other designs). Overall, the triangular fin design shows potential to be used in, for example, automotive applications due to its high performance as well as lightweight and compact design.

J. Lobato, P. Can˜izares, M. A. Rodrigo et al.

ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology • 2008

With the aim of improving the ethanol oxidation in fuel cells, researchers have developed numerous catalysts to break up the C-C bond. Most of the tests have been carried out at low temperature, using Nafion membrane as electrolyte. The cell performance of the Direct Ethanol Fuel Cells (DEFCs) at low temperature is still far from its industrial application. To improve the DEFC power density, high temperature operation (150–200 °C) has been suggested to promote the complete oxidation of ethanol. Thus, three different catalysts (Pt-Ru (1:1), Pt-Sn (1:1) and Pt-Sn-Ru (1:1:0.3), all of them supported on both non-activated and activated carbon were tested in H3PO4 doped PBI-based fuel cell, using vapour fed ethanol, operating in the range of 150–200 °C, and high ethanol concentration 6.7 M. The catalyst were synthesized using NaBH4 as reducing agent and were characterized by XRD, ICP-AES and TPR analyses. The best performance was reached at the highest temperature and with the catalyst based on Pt-Ru. The best results for the Ru-based catalyst can be explained by the higher level of alloying reached for the Ru than for Sn, which modifies the crystalline structure of Pt and enhances the activity oxidation of ethanol and of intermediates that are generated during the oxidation of ethanol.

T. Uma, M. Nogami

Fuel Cells • 2007

Abstract A novel structure for an H 2 /O 2 fuel cell with a proton conducting glass electrolyte and a Pt/C catalyst was developed. The performance of the fuel cell, which was impregnated with a glass electrolyte and a gaseous hydrogen–oxygen feed at low temperature in a humidified atmosphere was significantly improved by introducing membrane electrode assemblies (MEAs) consisting of heteropolyacids (HPAs) (phosphotungstic acid, PWA and phosphomolybdic acid, PMA) doped with a P 2 O 5 ‐SiO 2 glass electrolyte. The HPAs containing porous glass electrolytes show promise for applications in low temperature H 2 /O 2 fuel cells. The electrochemical behaviour of these materials was studied by measuring the current–voltage profile from polarisation curves. A maximum power density of ≈ 35 mW cm –2 was obtained at 30 °C and 30% RH (relative humidity) using a PMA/PWA‐P 2 O 5 ‐SiO 2 glass electrolyte membrane. The impedance measurements displaying the total cell ohmic resistance for 12 h at 0.5 V were evaluated at 30 °C. The resistance value was 3.5 Ω for an operating time of 12 h. This MEA showed the best and the most stable performance for use in an H 2 /O 2 fuel cell.

Pavlina Theodosiou, John Greenman, Ioannis Ieropoulos

ECS Meeting Abstracts • 2018

Introduction Biological fuel cells (BFCs) are an increasingly growing area of research as it beholds long-term sustainable advantages over conventional fuel cells. Microbial Fuel Cells (MFCs) are just one type of BFCs, which as the name implies, employ microbial electroactive species to facilitate the conversion of chemical energy stored in organic matter, into electricity. The properties of MFCs have successfully made the technology a primary source of energy for low-power autonomous robots 1 and off-grid urinal units 2 . However, a hindrance to the mass production of MFC units is the time-consuming assembly process, which could perhaps be overcome using additive manufacturing (AM) processes. AM or 3D-printing has played an increasing role in advancing the MFC technology, by substituting essential structural components i.e. chassis and separators, with 3D-printed parts 3,4 . This is precisely the line of work in the EVOBLISS project, which is investigating materials that can be extruded from the EVOBOT platform 5 for a potentially monolithically printed MFC. The development of such inexpensive, conductive, printable electrode material is described below as well as the advances of this material as a cathode electrode on air-breathing cathodes. Material and Methods Three triplicates of analytical size MFCs were assembled for this experiment using laser-cut acrylic sheets. The MFCs had a 25mL anode chamber, a CMI-700 cation exchange membrane (Membrane International, USA) as separator and three different electrodes forming the air-breathing cathodes. A gas diffusion electrode with polytetrafluoroethylene (PTFE) (60% wt. Sigma Aldrich, UK) painted carbon veil sheet that acted as the hydrophilic supporting material for a microporous layer (MPL) was used as the control. This was prepared with a mixture of activated carbon (80 g/120 mL solution. G Baldwin & Co, UK), PTFE and distilled water. The materials tested were a) a solid commercially available sintered Carbon Block CTO (Water Filter Man LTD, UK) and b) a custom made activated carbon-alginate paste which was made using ground activated carbon (80g) and alginate (Minerals Water Ltd, 20 g) that was then mixed with distilled water until a thick paste was made. The paste was then extruded from a syringe directly onto the membrane (10 ml) and dried/solidified on the bench for 24 hrs. The final weight of all the dried electrodes was 3.8 ± 0.2 g. The cells were inoculated with activated sludge (Wessex Water, UK) supplemented with full strength Tryptone Yeast Extract (1.5% w/v) and fed with human urine. Results The results showed that the MFCs using alginate electrode as cathode electron and oxygen receiver performed better compared to the MPL or sintered carbon having a maximum power transfer point at 286 μW, 98 μW and 85 μW respectively. An important factor to consider in the effort to improve the MFC performance is not only the power output but also the cost effectiveness of the materials, especially when using alginate. MPL cathode electrode requires a PTFE coated carbon veil sheet as well as a mixture of PTFE and carbon. PTFE is a highly toxic and expensive material (£138/500ml, Sigma Aldrich, 2017) compared to food grade alginate which only costs £8.76 per 500g. Moreover, the alginate electrode does not require a supporting material thus the cost was reduced further by removing the carbon veil from the assembly. Conclusion In conclusion, this experiment demonstrated that the development of an air-dried, extrude-able electrode material (similar to 3D printing) could successfully be incorporated in an MFC system and act as a cathode electrode. Such a development brings the field a step closer to monolithically printable MFCs, which can be made using the EVOBOT platform. References I. Ieropoulos, J. Greenman, C. Melhuish, and I. Horsfield, in Artificial Life Models in Hardware , p. 185–211 (2009). I. A. Ieropoulos et al., Environ. Sci. Water Res. Technol. , 2 , 336–343 (2016). J. You, R. J. Preen, L. Bull, J. Greenman, and I. Ieropoulos, Sustain. Energy Technol. Assessments , 19 , 94–101 (2017). H. Philamore, J. Rossiter, P. Walters, J. Winfield, and I. Ieropoulos, J. Power Sources , 289 , 91–99 (2015). A. Faíña, F. Nejatimoharrami, and K. Stoy, in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) , (2015).

Sarah Rita Maria Brunschweiger, Thomas Hofmann

Lebensmittelchemie • 2023

The chemical energy hidden in wastewater can be extracted, turning an energy‐intensive treatment process into an energy‐independent one. However, conventional aerobic treat‐ ment is very energy intensive, and anaerobic treatment requires a post‐treatment step to meet stringent discharge requirements. Therefore, Microbial Fuel Cells (MFCs) have attracted a lot of attention because of their ability to extract electrical energy directly from wastewater during the treatment process. Since combustion losses can be avoided, theoretically the greatest energy value can be obtained from the organic load. However, most MFC research is currently still taking place on a laboratory scale in the treatment of synthetic or municipal wastewater. Commercialization of MFC technology will require large‐scale plants, for which a suitable MFC design and operation concepts must first be identified, since neither configuration nor operating system has been clearly established yet. In addition, no specific concepts and application fields currently exist for the treat‐ ment of industrial wastewater. Consequently, with regard to MFCs in industrial wastewater treatment, the aim of this work is to develop a benchmark that serves for modeling the required overall efficiency of MFCs and to identify the most relevant key factors in order to derive enhancement strate‐ gies. By providing an overview of current MFCs in industrial wastewater treatment and developing a benchmark, the targets for long‐term operation of MFCs can be established allowing critical factors for design and operation to be identified. The resulting enhance‐ ment strategies were validated and the overall evaluation with the developed benchmark allowed an assessment regarding the commercialization potential. Compared to the first MFC design (MFC 1.0), the enhanced MFC design (MFC 2.0) increased the power density by a factor of up to 11 and extended the long‐term stability to one year by increasing the specific cathode surface area and reducing the electrode spacing in conjunction with avoiding fiber clogging on the anode side. In addition to using beneficial brewery wastewater with high content of easily degradable organic acids and high conductivity, the performance of the MFC was further stabilized and improved by changing the operating mode to continuous operation and reducing the hydraulic re‐ tention time to 6 h, resulting in a mean organic removal rate of 6.5 ± 1.9 kg/(m 3 · d). Although the overall energy efficiency is low compared to anaerobic treatment, the enor‐ mous wastewater treatment potential forms the basis for MFCs to become an alternative to conventional treatment technologies if self‐sufficient treatment is targeted. Due to the wide range of operating conditions and the modularity of stack systems, MFCs can become a promising option especially for industrial wastewater treatment.

Zhaoqi Ji, Maria Perez-page, Romeo Gonzalez Rodriguez et al.

ECS Meeting Abstracts • 2019

With the increasing contamination and depletion problems of fossil fuel, an alternative technology, the proton exchange membrane fuel cells (PEMFCs), has been considered as the most promising power source of the future in the field of the portable electrics and vehicles. The hydrogen fuel cell is expected to be the excellent choice because of its zero-carbon emission and high power density among variable fuel cells. Platinum (Pt) nanoparticles are the most widely used catalyst in the hydrogen fuel cell as it has high activity and selectivity for the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR). However, the utilization of precious platinum catalyst also has many shortcomings such as Pt agglomeration, which decrease the life time of the PEMFC, and the high cost of this material. Decreasing the loading of Pt on electrodes, cathode and anode, is one of the most important challenges for this field. Catalyst support materials with high surface area, high electrical conductivity and good catalyst interaction may decrease the amount of catalyst needed and improve the catalytic efficiency. With this aim, many carbon materials such as carbon black, Vulcan XC-72, mesoporous carbon and carbon nanotubes have been investigated as a catalyst support in the hydrogen fuel cell [1, 2]. Graphene, a two-dimensional (2D) structure of honeycomb lattice material, exhibits excellent electrical conductivity (104.36 S·cm -1 ), large specific surface area (~2630 m 2 ·g -1 ), good thermal and mechanical stability, has recently attracted great attention as a catalyst support [3]. Several publications have successfully developed Pt catalyst supported on reduced graphene oxide (rGO) to improve the PEMFCs performance. This process of synthesizing Pt-graphene based catalyst mostly starts from graphene oxide (GO) produced by Hummers method, which leads to environmental and safety issues (use KMnO4, strong oxidizing agents and concentrated H 2 SO 4 ), takes a long time and costly [4]. This work presents an alternative to Hummer’s method to produce GO and rGO by the Electrochemical Exfoliation of Graphite. A simple two electrodes configuration, counter electrode in different electrolyte solutions (NH 4 NO 3 or (NH 4 ) 2 SO 4 ) has been carried out to produce high quality exfoliated graphene oxide (EGO) in a fast, efficient and environmental friendly way, producing also high yield in comparison with the traditional Hummer’s method. Additionally, the functional groups of nitrogen and sulphur coming from the electrolyte solution are able to be introduced into EGO, which influence the local electronic structure as well as improve polarization of the graphene network [5, 6]. Therefore, this study presents an environmentally friendly and a cost-effective approach to prepare. Pt nanoparticles supported on EGO, which were synthesized by a modified polyol reduction method to compare with the traditional Pt supported on carbon black (Pt-CB) and rGO produced by Hummers’ method (Pt-GO) to improve the efficiency and the long time performance of a PEMFCs. Successful preliminary results can be observed in Fig 1, which shows that Pt-EGO can improve the electrochemical surface area (ECSA) over Pt-CB and Pt-GO. Meanwhile, Pt-EGO can influence the durability of the catalyst with chrono amperometry measurement. This study will discuss the characterisation of developed catalysts and their efficacy in a working fuel cell system. References [1] Jing Liu, Xiaoxia Wu, Liping Yang, Fu Wang, Jiao Yin. Unprotected Pt nanoclusters anchored on ordered mesoporous carbonas an efficient and stable catalyst for oxygen reduction reaction. Electrochimica Acta . 2019. 297, 539-544. [2] Kentaro Ichihashi, Satoshi Muratsugu, Shota Miyamoto, Kana Sakamoto, Nozomu Ishigurob, Mizuki Tada. Enhanced oxygen reduction reaction performance of size-controlled Pt nanoparticles on polypyrrole-functionalized carbon nanotubes. Dalton Transactions . 2019. [3] María Pérez Page, Madhumita Sahoo, Stuart M. Holmes. Single Layer 2D Crystals for electrochemical applications of ion exchange membranes and hydrogen evolution catalysts. Advanced Materials Interfaces . 2019. 1801838. [4] Erwan Bertin, Adrian Münzer, Sven Reichenberger, Rene Streubel, Thomas Vinnay, Hartmut Wiggers, Christof Schulz, Stephan Barcikowski, Galina Marzun. Durability study of platinum nanoparticles supported on gas-phasesynthesized graphene in oxygen reduction reaction conditions. Applied Surface Science . 2019. 467-468, 1181-1186. [5] Two-Step Electrochemical Intercalation and Oxidation of Graphite for the Mass Production of Graphene Oxide. Jianyun Cao, Pei He, Mahdi A. Mohammed, Xin Zhao, Robert J. Young, Brian Derby, Ian A. Kinloch, Robert A. W. Dryfe. Journal of the American Chemical Society . 2017. 139, 17446-17456. [6] R. Imran Jafri, N. Rajalakshmi, S. Ramaprabhu. Nitrogen doped graphene nanoplatelets as catalyst support for oxygen reduction reaction in proton exchange membrane fuel cell. Journal of Material Chemistry . 2010. 20, 7114-7117. Figure 1

Bin Du, Richard Pollard, Manikand Ramani et al.

ECS Transactions • 2007

Rapid fuel cell performance degradation was observed after just 30 cold start/hot stop cycles. Relative humidity (RH) was found to be the primary operating parameter associated with the rapid voltage decay during this thermal cycling. It was found that repeated thermal cycling could affect the RH inside a fuel cell and, consequently, alter the water activity of membrane/ionomer. We propose an extension of the generally accepted reverse-current carbon corrosion mechanism to account for the RH effects. The rapid voltage decay was linked to a RH- dependent cathode carbon corrosion process which was attributed to a lag in the ionomer/membrane hydration state during the thermal cycling. It has been demonstrated that one can reduce the carbon corrosion rate by avoiding the combination of cold starts and hot stops. Recommended strategies for mitigation are discussed in the context of the corrosion mechanism.

Chanho Pak, Hyeon Seung Jung, Do-Hyung Kim et al.

ECS Meeting Abstracts • 2022

Catalyst double layer (CDL) structure on gas diffusion electrode (GDE) without microporous layer (MPL) is developed for the anode of high temperature polymer electrolyte membrane fuel cell (HT–PEMFC). Polytetrafluoroethylene and polyvinylidene fluoride is applied for the outer and inner layer as the hydrophobic binder for fabricating 3D electrode structure. The effect of Pt ratio in anode CDLs on the GDE performance was investigated by single cell test and electrochemical analysis using poly(benzimidazole) (PBI)–based membrane, with Pt loading under 0.3 mg/cm 2 at ambient pressure air on 150℃. The results show that optimal CDL anodes present performance of 0.65V at 0.2A/cm 2 and peak power density is 0.41W/cm 2 at mass transfer region which is higher than conventional single layer anode with MPL. Furthermore, the 3D structure of the outer catalyst layer in anode read high catalyst utilization and preventing leakage of electrolyte with a short–term durability test shows good stability with PBI membrane.

D. Fuerth, A. Bazylak

ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology • 2012

In this work, we present an experimental microfluidic fuel cell with a novel up-scaled porous electrode architecture that provides higher overall power output compared to conventional microfluidic fuel cells and a methodology for electrode material evaluation to inform designs for improved performance. Our proof-of-concept architecture is an up-scaled version of a previously presented flow-through cell with more than nine times the active electrode surface area. We employed 0.04M formic acid and 0.01M potassium permanganate as fuel and oxidant, respectively, dissolved in a 1M sulfuric acid electrolyte. Platinum black was employed as the catalyst for both anode and cathode. Carbon based porous electrodes including felt, cloth, fibre, and foam were compared to traditional Toray carbon paper in order to characterize their respective performances. We also discussed current densities normalized by electrode volume, which is appropriate for comparison of flow-through architectures. The traditional method of current normalization by projected electrode surface area is also presented.

K. Rabaey, W. Ossieur, M. Verhaege et al.

Water Science and Technology • 2005

Microbial fuel cells which are operated in continuous mode are more suitable for practical applications than fed batch ones. Three influent types containing carbohydrates were tested, i.e. a glucose medium, a plant extract and artificial wastewater. The anode reactor compartment yielding the best results was a packed bed reactor containing graphite granules. While in non-mediated batch systems power outputs up to 479 W m−3 of anode compartment could be attained; in continuous mode the power outputs were limited to 49 W m−3. Cyclic voltammetry was performed to determine the potential of the in-situ synthesized bacterial redox mediators. Addition of mediators with a potential similar to the bacterial potential did not significantly alter the MFC power output, indicating a limited influence of soluble mediators for continuous microbial fuel cells. Maximum coulombic and energy conversion efficiencies were, for the continuous microbial fuel cell operating on plant extract at a loading rate of 1 kg COD m−3 of anode compartment per day, 50.3% and 26.0% respectively.

Li-Chun Wu, Teh-Hua Tsai, Man-Hai Liu et al.

Sensors • 2017

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5–9, 20–35 °C, coexisting ions, and salinity of 0–15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m2 at 1500 Ω. A good linear relationship (r2 = 0.997) was observed between the Cr(VI) concentration (2.5–60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (−6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations.

Alessandro Iannaci, Adam Myles, Timothé Philippon et al.

Molecules • 2021

Surface modification of electrodes with glycans was investigated as a strategy for modulating the development of electrocatalytic biofilms for microbial fuel cell applications. Covalent attachment of phenyl-mannoside and phenyl-lactoside adlayers on graphite rod electrodes was achieved via electrochemically assisted grafting of aryldiazonium cations from solution. To test the effects of the specific bio-functionalities, modified and unmodified graphite rods were used as anodes in two-chamber microbial fuel cell devices. Devices were set up with wastewater as inoculum and acetate as nutrient and their performance, in terms of output potential (open circuit and 1 kΩ load) and peak power output, was monitored over two months. The presence of glycans was found to lead to significant differences in startup times and peak power outputs. Lactosides were found to inhibit the development of biofilms when compared to bare graphite. Mannosides were found, instead, to promote exoelectrogenic biofilm adhesion and anode colonization, a finding that is supported by quartz crystal microbalance experiments in inoculum media. These differences were observed despite both adlayers possessing thickness in the nm range and similar hydrophilic character. This suggests that specific glycan-mediated bioaffinity interactions can be leveraged to direct the development of biotic electrocatalysts in bioelectrochemical systems and microbial fuel cell devices.

Priyadharshini Mani, Fidal V T, Kyle Bowman et al.

Environmental Microbiology Reports • 2020

Summary Microbial biocathodes are gaining interest due to their low cost, environmental friendliness and sustainable nature. In this study, a microbial consortium was enriched from activated sludge obtained from a common textile effluent treatment plant in the absence of organic carbon source to produce an electroactive biofilm. Chronoamperometry method of enrichment was carried out for over 70 days to select for electroactive bacteria that could be used as a cathode catalyst in microbial fuel cells (MFC). The resultant biofilm produced an average peak current of −0.7 mA during the enrichment and produced a maximum power density of 64.6 ± 3.5 mW m −2 compared to platinum (72.7 ± 1.2 mW m −2 ) in a Shewanella ‐based MFC. Microbial community analysis of the initial sludge sample and enriched samples, based on 16S rRNA gene sequencing, revealed the selection of chemolithotrophs with the most dominant phylum being Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria and Acidobacteria in the enriched samples. A variety of CO 2 fixing and nitrate‐reducing bacteria was present in the resultant biofilm on the cathode. This study suggests that microbial consortia are capable of replacing expensive platinum as a cathode catalyst in MFCs.

Nadiyah Faizi Polontalo, Falvocha Alifsmara Joelyna, Abdullah Malik Islam Filardli et al.

E3S Web of Conferences • 2020

Nowadays, Indonesia is faced with an increase in human growth, and followed by increasing electricity demand. One of the environmental friendly alternative energy that can solve this problem is microbial fuel cell, which utilizes organic matter as a substrate of bacteria in carrying out its metabolic activities to produce electricity. In this study, investigated the electrical energy produced by Microalgae Microbial Fuel Cell (MMFC) using Chlorella vulgaris and “Batik” wastewater. This study aims to assess the performance of the MMFC system based on the influence of yeast (8 g L−1 and 4 g L −1 ), “Batik wastewater” concentration (50 % and 100 %), and graphite electrodes (1:1 and 2:2). The MMFC system was carried out by filling anode chamber with “Batik” wastewater and the cathode with C. vulgaris . MMFC simulation was operated for 7 d. Concentration of 100 % “Batik” wastewater and 2:2 number of electrodes gave the best result in MMFC with voltage 0.115 Volt, algae absorbance 0.666. The COD decreased from 824 mg L −1 to 752 mg L −1 after the MMFC. The addition of 8 g L −1 yeast gave the optimum of bioelectricity production reached 0.322 Volt and the microalgae grew until the absorbance reached 1.031.

Muhammad Imran Din, Mahmood Ahmed, Muhammad Ahmad et al.

Journal of Chemistry • 2023

Microbial fuel cells (MFCs), a technology that converts chemical energy into electrical energy, have been regarded as the most suitable method for sustainable energy production. However, most MFCs generate a low power output, limiting their large-scale industrial applications. Here, we introduce a high-performancesingle-chambered microbial fuel cell (SCMFC) based on carbon fiber anode and zinc oxide nanoparticle (ZnO NP)-fabricated copper cathode. Furthermore, best optimized conditions of temperature, pH, substrate, external resistance, and cathode fabrication were also considered to evaluate the performance of this SCMFC in treating potato wastewater along with bioenergy production. Results indicated that chemical oxygen demand (COD) could be effectively removed (80%) and maximum voltage, current density, and power density were 1.58 V, 0.235 mA/cm2, and 0.3714 mW/cm2, respectively. Hence, the SCMFC used in this study has a higher potential to treat potato wastewater along with high power production.

Leila Davarpanah, Farimah Sarbisheh, Elham Abdollahzadeh Sharghi

Journal of Chemical Technology & Biotechnology • 2020

Abstract BACKGROUND A high nitrate concentration in groundwater in some parts of Iran has been detected due to untreated wastewater discharge and agriculture activities. Therefore, the development of treatment technology in this area using a new biological method was carried out. RESULTS Activated sludge originating from slaughterhouse wastewater treatment plants and immobilized on graphite granules exhibited noticeable denitrification activity in a double chamber upflow tubular microbial fuel cell (UTMFC). The effects of three C/N values at different initial nitrate concentrations and external resistances on nitrate and chemical oxygen demand (COD) removal efficiencies as well as cell performance were studied at a fixed hydraulic retention time (HRT) of 12 h. Based on nucleotide sequence of 16S rRNA, four bacterial strains from anodic biofilm were also identified. The UTMFC operated in a continuous mode with C/N values of 20 and 10 was able to denitrify up to 150 mg L –1 nitrate without more accumulation of nitrite and ammonium ions than is permitted for drinking water. The maximum nitrate removal capacity of 0.25 ± 0.01 kg NO 3 − ‐N/ (m 3 net anodic compartment ‘NAC’.day) was achieved at 400 mg L –1 initial nitrate concentration and at C/N = 10. Additionally, the maximum current density and power generation at this ratio were found to be 46.04 A m –3 NAC and 16.96 W/m 3 NAC, respectively. No efficient denitrification was observed at C/N = 5 while nitrite/ammonium formation increased. CONCLUSION The experimental data documented the feasibility of bioelectricity generation and substrate removal utilizing acetate containing water under the adopted operating conditions of UTMFC, and the proposed system allowed the simultaneous heterotrophic denitrification/electricity generation. © 2020 Society of Chemical Industry

S R Juliastuti, R Darmawan, N Hendrianie et al.

IOP Conference Series: Materials Science and Engineering • 2019

Abstract Chromium (Cr) and manganese (Mn) are heavy metals which have high oxidation potential and cause mutagenesis and carcinogenic to living organisms. Microbial Fuel Cell (MFC) appears as one of the applications in the processing of Cr and Mn metals. MFC is bioreactor which converts chemical energy of organic compounds into electrical energy through the catalytic reaction of microorganisms in anaerobic conditions. The aim of this research are to find out the role of Shewanella oneidensis MR-1 bacteria on manufacture electrical energy by utilizing organic wastes, and to find out the concentration of Shewanella oneidensis MR-1 on the most influential anode side for the reduction of metallic Cr, Mn, and its mixed metal on the cathode side by using a MFC. The research method used molasses with bacteria concentration of 10%; 12.5%; 15% (v/v) on the anode side, while on the cathode side was used Cr(VI), Mn(VII) solutions, and mixtures of Cr and Mn solutions with the ratio of 1:0; 0:1; 1:1 (w/w). 15% bacteria concentration on mixture of metal solution resulted the highest electricity production, which was 46.33 (mW/m 2 ), and the best reduction of Cr 6+ to Cr 3+ 82.15%, while for the reduction of Mn 7+ to Mn 2 was 61.17%.

Toyoaki Matsuura, Jason B. Siegel, Jixin Chen et al.

ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology • 2010

Dead-ended anode (DEA) operation of Polymer Electrolyte Fuel Cell (PEFC) can simplify the fuel cell auxiliary and reduce system cost, however durability and lifetime in this operating mode requires further study. In this work, we investigate the electrode and membrane degradations of one 50 cm2 active area fuel cell under DEA operation using a combination of post-mortem evaluation and in-situ performance evaluation protocol. We experimentally identify multiple degradation patterns using a cell which we have previously modeled and experimentally verified the spatio-temporal patterns associated with the anode water flooding and nitrogen blanketing. The change in cell voltage and internal resistance during operation and ex situ Scanning Electron Microscope (SEM) images of aged electrode/membrane are analysed to determine and characterize the degradation of the membrane electrode assembly (MEA). Chemical degradations including carbon corrosion in the catalyst layer and membrane decomposition are found after operating the cell with a DEA. Mechanical degradations including membrane delamination are also observed. Unique features of DEA operation including fuel starvation/nitrogen blanketing in the anode and uneven local water/current distribution, are considered as culprits for degradation.

Jae Hyeok Lee, Junmo Koo, Jun Woo Kim et al.

ECS Meeting Abstracts • 2018

Polymer Electrolyte Membrane Fuel Cells (PEMFCs) has been drown much attentions due to its high energy density, pollution-free electricity generation. Because of its versatile advantages, PEMFCs are considered as next-generation transportation system, which is used for power system of fuel cell electronic vehicle (FCEV). However, the usage of Pt catalyst hinders the widespread application of PEMFC because of high price of Pt. In order to utilize Pt in cost-effective way, various researches have been conducted to maximize the performance and long-term stability of Pt catalyst. Recently, many researches of Pt-metal oxide/C catalyst in PEMFCs have been investigated due to improvement of adsorption characteristics for oxygen at the surface of Pt by adding metal oxide. Especially, Cerium oxide has superior oxygen storage capability originated from easy redox between Ce 3+ and Ce 4+ . Also, Pt-CeO x interact regions increase active sites where oxygen and Pt catalyst could meet together. In this study, we treated PEMFC cathode by cerium oxide with infiltration process, which enables uniform distribution of added materials with cost-effective way. We investigated the performance of PEMFC membrane-electrode assembly (MEA) with cerium oxide treated cathode. PEMFC performance was evaluated by current-voltage measurement and cyclic voltammetry. Also, the long term stability of cerium oxide treated PEMFC MEA has been analyzed with electrocatalyst accelerated degradation protocol proposed by Department of Energy (DOE). In brief, performance and long term stability enhancement of PEMFC MEA has been observed in cerium oxide treated samples. In our presentation, detail process of experiment and PEMFC performance analysis will be introduced.