Pt-SnOx Clusters With Weak Interfacial Interaction Boost Hydrogen Evolution.

Downsizing noble metal catalysts (e.g., Pt) is critical for enhancing atomic efficiency in sustainable energy applications. Herein, we report a Pt-SnOx nanocluster (NC) system featuring weak Pt/SnOx interfacial interaction, which enables SnOx to effectively modulate the reaction pathway without compromising the intrinsic Pt catalytic properties. Notably, characterization results reveal negligible charge transfer at the interface. The Pt-SnOx NCs exhibit an overpotential of 22 mV at 10 mA cm-2 and a Tafel slope of 24 mV dec-1, outperforming Pt NCs, Pt nanoparticles, and Pt-SnO2 structures with strong interfacial interactions. Theoretical calculations suggest that the Pt-SnOx architecture facilitates hydrogen spillover, which may promote a shift in the dominant hydrogen evolution reaction (HER) mechanism from Volmer-Heyrovsky to a more efficient Volmer-Tafel route. As the cathode in an ethanol-assisted proton exchange membrane paired-electrolyzer, the Pt-SnOx NC catalyst delivers 1.0 A cm-2 at below 1.5 V under 80°C with stable operation over 70 h.