scholarly journals CO 2 Reduction: Highly Efficient Electrochemical CO 2 Reduction Reaction to CO with One‐Pot Synthesized Co‐Pyridine‐Derived Catalyst Incorporated in a Nafion‐Based Membrane Electrode Assembly (Adv. Energy Mater. 39/2020)

2020 ◽  
Vol 10 (39) ◽  
pp. 2070164
Author(s):  
Naohiro Fujinuma ◽  
Atsushi Ikoma ◽  
Samuel E. Lofland
Keyword(s):  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Membrane Electrode ◽  
One Pot ◽  
Highly Efficient ◽  
Energy Mater

scholarly journals MOF Derived Catalysts for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell

2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Exchange Membrane

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.

Impedance-based Performance Analysis of Micropatterned Polymer Electrolyte Membrane Fuel Cells

2021 ◽  
pp. 1-33
Author(s):  
Morio Tomizawa ◽  
Keisuke Nagato ◽  
Kohei Nagai ◽  
Akihisa Tanaka ◽  
Marcel Heinzmann ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Electrochemical Impedance ◽  
Catalyst Layer ◽  
Membrane Electrode Assembly ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Membrane Electrode

Abstract Micropatterns applied to proton exchange membranes can improve the performance of polymer electrolyte fuel cells; however, the mechanism underlying this improvement is yet to be clarified. In this study, a patterned membrane electrode assembly (MEA) was compared with a flat one using electrochemical impedance spectroscopy and distribution of relaxation time analysis. The micropattern positively affects the oxygen reduction reaction by increasing the reaction area. However, simultaneously, the pattern negatively affects the gas diffusion because it lengthens the average oxygen transport path through the catalyst layer. In addition, the patterned MEA is more vulnerable to flooding, but performs better than the flat MEA in low-humidity conditions. Therefore, the composition, geometry, and operating conditions of the micropatterned MEA should be comprehensively optimized to achieve optimal performance.

scholarly journals Activation of bimetallic PtFe nanoparticles with zeolite-type cesium salts of vanadium-substituted polyoxometallates toward electroreduction of oxygen at low Pt loadings for fuel cells

2021 ◽  
Author(s):  
Marco Renzi ◽  
Francesco Nobili ◽  
Krzysztof Miecznikowski ◽  
Aldona Kostuch ◽  
Anna Wadas ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Relative Humidity ◽  
Stress Test ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Composite Catalyst ◽  
Membrane Electrode ◽  
Cell Potential ◽  
Zeolite Type ◽  
Low Pt Loading

AbstractThe catalytic activity of commercial carbon-supported PtFe (PtFe/C) nanoparticles admixed with mesoporous polyoxometalate Cs3H3PMo9V3O40, (POM3-3–9), has been evaluated towards oxygen reduction reaction (ORR) in acid medium. The polyoxometalate cesium salt co-catalyst/co-support has been prepared by titration using the aqueous solution of phosphovanadomolibdic acid. The synthesized material has been characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results confirm formation of the polyoxometalate salt with the characteristic Keggin-type structure. The composite catalyst has been prepared by mixing the POM3-3–9 sample with the commercial PtFe/C by sonication. The diagnostic rotating ring-disk voltammetric studies are consistent with good performance of the system with low Pt loading during ORR. The fuel cell membrane electrode assembly (MEA) utilizing the PtFe/POM-based cathode has exhibited comparable or better performance (at relative humidity on the level of 100, 62, and 17%), in comparison to the commercial MEA with higher Pt loading at the cathode. Furthermore, based on the cell potential and power density polarization curves, noticeable improvements in the fuel cell behavior have been observed at the low relative humidity (17%). Finally, the accelerated stress test, which uses the potential square wave between 0.4 V and 0.8 V, has been performed to evaluate MEA stability for at least 100 h. It has been demonstrated that, after initial losses, the proposed catalytic system seems to retain stable performance and good morphological rigidity.

scholarly journals Monodispersed Pt3Ni Nanoparticles as a Highly Efficient Electrocatalyst for PEMFCs

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 588 ◽  
Author(s):  
Delong Yang ◽  
Jun Gu ◽  
Xiaomeng Liu ◽  
Haitong He ◽  
Meiyu Wang ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Reduction Process ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Electrochemical Surface Area ◽  
Oxygen Reduction Reaction Activity ◽  
Mass Activity ◽  
Exchange Membrane

A facile strategy is proposed to synthesize monodispersed Pt3Ni nanoparticles. Such a kind of electrocatalyst shows a larger electrochemical surface area (98.9 m2 gpt−1) and double the mass activity of the oxygen reduction reaction activity compared to commercial Pt/C catalyst. The results show that the suitable addition of Ni and triethylamine in the reduction process plays an important role in controlling the size and dispersion of Pt3Ni nanoparticles. A further membrane electrode assembly test proves that as-prepared Pt3Ni nanoparticles can greatly enhance the electrochemical performance of a proton exchange membrane fuel cell, which exhibits a great potential of application in fuel cells.

A cost-effective and highly efficient dissymmetric membrane electrode assembly designed for fuel cells

2021 ◽  
Vol 489 ◽  
pp. 229485
Author(s):  
Xue Gong ◽  
Mingbo Ruan ◽  
Ping Song ◽  
He Li ◽  
Jing Cao ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Cost Effective ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Highly Efficient

scholarly journals Silica-copper catalyst interfaces enable carbon-carbon coupling towards ethylene electrosynthesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Li ◽  
Adnan Ozden ◽  
Mingyu Wan ◽  
Yongfeng Hu ◽  
Fengwang Li ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Copper Catalyst ◽  
Scale Up ◽  
Coupling Reaction ◽  
Density Functional Theory Calculations ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
One Pot ◽  
Sustained Operation

AbstractMembrane electrode assembly (MEA) electrolyzers offer a means to scale up CO2-to-ethylene electroconversion using renewable electricity and close the anthropogenic carbon cycle. To date, excessive CO2 coverage at the catalyst surface with limited active sites in MEA systems interferes with the carbon-carbon coupling reaction, diminishing ethylene production. With the aid of density functional theory calculations and spectroscopic analysis, here we report an oxide modulation strategy in which we introduce silica on Cu to create active Cu-SiOx interface sites, decreasing the formation energies of OCOH* and OCCOH*—key intermediates along the pathway to ethylene formation. We then synthesize the Cu-SiOx catalysts using one-pot coprecipitation and integrate the catalyst in a MEA electrolyzer. By tuning the CO2 concentration, the Cu-SiOx catalyst based MEA electrolyzer shows high ethylene Faradaic efficiencies of up to 65% at high ethylene current densities of up to 215 mA cm−2; and features sustained operation over 50 h.

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