Optimization of ionomer-free ultra-low loading Pt catalyst for anode/cathode of PEMFC via magnetron sputtering. (19th July 2019)

• Record Type: Journal Article
• Authors: Ostroverkh, Anna; Johánek, Viktor; Dubau, Martin; Kúš, Peter; Khalakhan, Ivan; Šmíd, Břetislav; Fiala, Roman; Václavů, Michal; Ostroverkh, Yevhenii; Matolín, Vladimír
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 35(2019)
• Page Start: 19344
• Page End: 19356
• Publication Date: 2019-07-19
• Subjects: Ionomer-free catalyst -- Ultra-low platinum membrane electrode assembly (MEA) -- Proton exchange membrane fuel cell (PEMFC) -- Magnetron sputtering -- Nitrogenated carbon -- Hydrogen; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.12.206
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In this study, thin-film Pt catalysts with ultra-low metal loadings (ranging from 1 to 200 μg cm −2 ) were prepared by magnetron sputtering onto various carbon-based substrates. Performance of these catalysts acting as anode, cathode, or both electrodes in a proton exchange membrane fuel cell (PEMFC) was investigated in H2 /O2 and H2 /air mode. As base substrates we used standard microporous layers comprising carbon nanoparticles with polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene (FEP) supported on a gas diffusion layer. Some substrates were further modified by magnetron sputtering of carbon in N2 atmosphere (leading to CNx ) followed by simultaneous plasma etching and cerium oxide deposition. The CNx structure exhibits higher resistance to electrochemical etching as compared to pure carbon as was determined by mass spectrometry analysis of PEMFC exhaust at different cell potentials for both sides of PEMFC. The role of platinum content and membrane thickness was investigated with the above four different combinations of ionomer-free carbon-based substrates. The results were compared with a series of benchmark electrodes made from commercially available state-of-the-art Pt/C catalysts. It was demonstrated that the platinum utilization in PEMFC with magnetron sputtered thin-film Pt electrodes can be up to 2 orders of magnitude higher than with the standard Pt/C catalysts while keeping the similar power efficiency and long-term stability. Highlights: Pt content in PEMFC was optimized via sputter-deposition of thin-film electrodes. Different porous carbon-based substrates without added ionomer were used. Pt on ceria-etched nitridized carbon interlayer proved to be the most efficient. Very high power densities were achieved with Pt loadings in μg.cm −2 range. Pt content in PEMFC dramatically reduced without curtailing power or durability.