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

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 (Pt₁) confined within N-doped hollow polyhedral carbons (Co_n-Pt₁@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 Pt₁ sites, thereby enhancing the HER through a short C site→C-Pt bridge site→Pt site hydrogen spillover pathway.