Co Nanoparticle: An Efficient H‐pump for Pt Single Atoms Towards Enhanced Hydrogen Spillover

Abstract Introducing OH‐interaction sites to accelerate water dissociation can increase hydrogen coverage on active site surfaces and thus accelerate H‐spillover, leading to an enhanced hydrogen evolution reaction (HER). Recent studies on single‐atom catalysts (SACs) combined with nano‐metal‐particles (NMPs) have developed various homologous NMP‐SACs, however, synthesizing the heterologous NMP‐SACs remains a significant challenge. Particularly for HER catalysts under alkaline conditions, the ideal heterologous structure requires a synergy between non‐noble NMPs with strong oxophilicity and noble‐metal SAs with suitable hydrogen binding energy. Herein, we report a facile pyrolysis‐confinement strategy to create the heterologous NMP‐SACs, comprising Co NMP (Co n ) and Pt SACs (Pt 1 ) confined within N‐doped hollow polyhedral carbons (Co n ‐Pt 1 @NPC). This catalyst demonstrates outstanding HER activity and superior stability in alkaline electrolyzer. Calculations reveal that Co nanoparticles serve as an H‐pump, dissociating water to supply hydrogen to Pt 1 sites, thereby enhancing the HER through a short C site→C−Pt bridge site→Pt site hydrogen spillover pathway.