Subsize Pt-based intermetallic compound enables long-term cyclic mass activity for fuel-cell reduction
H Cheng and RJ Gui and H Yu and C Wang and S Liu and HF Liu and TP Zhou and N Zhang and XS Zheng and WS Chu and Y Lin and HA Wu and CZ Wu and Y Xie, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 118, e2104026118 (2021).
Pt-based alloy catalysts may promise considerable mass activity (MA) for oxygen reduction but are generally unsustainable over long-term cycles, particularly in practical proton exchange membrane fuel cells (PEMFCs). Herein, we report a series of Pt-based intermetallic compounds (Pt3Co, PtCo, and Pt3Ti) enclosed by ultra thin Pt skin with an average particle size down to about 2.3 nm, which deliver outstanding cyclic MA and durability for oxygen reduction. By breaking size limitation during ordered atomic transformation in Pt alloy systems, the MA and durability of subsize Pt-based intermetallic compounds can be simultaneously optimized. The subsize scale was also found to enhance the stability of the membrane electrode through preventing the poisoning of catalysts by ionomers in humid fuel-cell conditions. We anticipate that sub size Pt- based intermetallic compounds set a good example for the rational design of high-performance oxygen reduction electrocatalysts for PEMFCs. Furthermore, the prevention of ionomer poisoning was identified as the critical parameter for assembling robust commercial membrane electrodes in PEMFCs.
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