Short‐path Hydrogen Spillover on CeO2‐Supported PtPd Nanoclusters for Efficient Hydrogen Evolution in Acidic Media

Hydrogen spillover in supported metal electrocatalysts has garnered significant research attention owing to its potential to enhance the efficiency of the hydrogen evolution reaction (HER). However, the design of such electrocatalysts faces critical challenges, including the facilitation of hydrogen spillover and the reduction of its associated energy barriers. Herein, PtPd alloy clusters are anchored to the CeO2 surface, enabling short-path hydrogen spillover in heterogeneous catalysts and lowering the reaction energy barrier in acidic environments. During the HER process, hydrogen is initially adsorbed on the noble metal surface and subsequently migrates to the interface, rather than precipitating directly on the CeO2 surface. This interface exhibits a near-zero Gibbs free energy of hydrogen adsorption (0.023 eV). Consequently, the catalyst demonstrates an exceptionally low overpotential of only 5.7 mV at 10 mA cm-2 in acidic media, along with remarkable long-term stability. These findings provide valuable insights into the development of highly efficient HER electrocatalysts for acidic environments based on hydrogen spillover mechanisms.