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Magnetron sputtered thin-film vertically segmented Pt-Ir catalyst supported on TiC for anode side of proton exchange membrane unitized regenerative fuel cells

Publikace na Matematicko-fyzikální fakulta |
2019

Tento text není v aktuálním jazyce dostupný. Zobrazuje se verze "en".Abstrakt

Dependence on noble metal catalysts is considered to be the main factor which hinders wider commercialization of proton exchange membrane fuel cells (PEM-FCs) and water electrolyzers (PEM-WEs). One way of lowering the loading of Pt and Ir is by using thin-film techniques for their deposition onto the high-surface conductive nanoparticles.

Another approach, which is convenient in applications where the complete cycle of electricity - > H-2 - > electricity takes place, is merging the PEM-WEs and PEM-FCs into one bi-functional system - the unitized regenerative fuel cell (PEM-URFC). In accordance with the above mentioned conception, this paper revolves around unconventionally prepared bi-functional magnetron sputtered lower-loading Pt-Ir catalysts for the anode side of PEM-URFC.

Two geometries of catalyst coated membranes (CCM) were compared, differing in relative positioning of individual Pt and Ir thin films sputtered on TiC-based support sublayer; the sandwich-like Ir/TiC/Pt structure and the co-sputtered Pt-Ir/TiC structure. Wide arsenal of analytical methods, ranging from photoelectron spectroscopy to electrochemical atomic force microscopy determined that co-sputtering of Pt and Ir leads to alloy formation, thus preventing iridium to fully electro-oxidize to IrOx which in turn helps to explain why sandwich-like Ir/TiC/Pt structure, with no alloy, outperforms the co-sputtered Pt-Ir/TiC CCM in both operational regimes despite having the exactly same noble metal loading.

The PEM-URFC single cell with sandwich-like bi-functional anode catalyst yielded 31.8% of round-trip efficiency at 1 A cm(-2) in comparison to 34.2% achieved by combination of single-purpose cells with more than double the loading of noble metals. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd.

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