Dynamic modulation of electron redistribution at the heterogeneous interface nickel hydroxides/platinum boosts acidic oxygen reduction reaction

The interfacial electron interactions in heterogeneous catalysts are critical in determining the adsorption strengths and configurations of reaction intermediates, which are essential for the efficiency of multistep tandem catalytic processes. Amorphous-crystalline (a-c) heterostructures have garnered significant interest due to their unusual atomic arrangements, adaptable electron configurations, and exceptional stability. Here, we introduce a mesoporous a-c heterojunction catalyst featuring enriched amorphous-crystalline Ni(OH)2/Pt boundaries (ac-Ni(OH)2@m-Pt), designed for efficient acidic oxygen reduction reaction (ORR). This catalyst enables electron redistribution at the heterogeneous interface, thereby enhancing both catalytic activity and durability. As anticipated, the ac-Ni(OH)2@m-Pt delivers a high mass activity (MA) of 0.95 A mgPt−1 and maintains good durability (89.8% MA retention) over 15000 cycles. Advanced characterization and theoretical calculations reveal that the catalyst's high performance stems from the dynamic heterogeneous-interface electron redistribution at the a-c interface. This dynamic-cycling electron transfer, driven by the applied potential, promotes O2 activation and accelerates the protonation of *O intermediate during ORR. This work offers a promising avenue for improving the design of electrocatalysts using a-c interface engineering. The acidic oxygen reduction reaction (ORR) plays a crucial role in proton-exchange membrane fuel cells. Here, the authors develop a mesoporous amorphous-crystalline (a-c) heterojunction catalyst which promotes the protonation of *O intermediate via dynamic a-c interface electron redistribution.