Revealing Hydrogen Evolution Performance of Single-Atom Platinum Electrocatalyst with Polyoxometalate Molecular Models

Single-atom catalysts (SACs) have attracted much attention due to their outstanding catalytic activity and maximum atom utilization. However, the unclear structure of the atomic active site hinders deep understanding and wide applications of SACs. Herein, we select a series of single-atom platinum (Pt)-containing polyoxometalates with well-defined structures as molecular models to clarify the effects of metal–oxide support and coordination environment on the activity of single-atom Pt electrocatalyst for HER. In situ X-ray absorption spectroscopy and density function theory calculation reveal that metal–oxide supports affect the ability of atomic Pt site to obtain electrons, resulting in different effective potentials loaded on the Pt active center in HER. Meanwhile, the coordination environment of single-atom Pt determines the pathway of HER, which also leads to different HER performance. This work provides a feasible strategy to reveal the structure–activity relationship of SACs and design new high-efficiency SACs for electrocatalytic HER.