Improving the oxygen reduction reaction (ORR) performance of platinum (Pt)-based catalysts is crucial for proton-exchange membrane fuel cells (PEMFCs). Although well-acknowledged strain effect and ligand effect have been widely applied to ORR catalysts, a continued push for higher activity and longer lifetime of the catalyst remains essential, which cannot be achieved by solely optimizing catalyst. This bottleneck requires effective breakthrough from other perspectives such as catalyst-interface properties that fundamentally determine physisorption the microkinetic yet have been largely overlooked. Herein, by combining experimental designs and molecular dynamics (MD) simulations with the interface force field (IFF), we propose that selected molecular ligands on the Pt surface can effectively disrupt the interfacial H2O network, which enables increased interfacial O2 concentration, longer O2 physisorption time and enhanced H2O desorption, leading to much improved ORR activity. We further demonstrated an optimal surface-modified PtCuNi catalyst, which doubled the specific activity of previously reported highest J-PtNWs. The modified catalysts also show a considerably extended lifetime compared to unmodified catalysts.

Boosting oxygen reduction reaction kinetics by interfacial Le Chatelier’s principle

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.