Unveiling the critical role of active site interaction in single atom catalyst towards hydrogen evolution catalysis

Abstract

Single atom catalysts (SACs) with efficient active sites are considered as valuable candidates to replace traditional catalysts. Fundamental insights into the interaction between single atom active sites, and its effect on the catalytic performance are still rare. Herein, we demonstrate the critical role of active site interaction in the intrinsic activity of SACs during acidic hydrogen evolution catalysis. Different amounts of platinum (Pt) atoms were atomically dispersed on graphitic carbon supports (PtSACs) to vary the spatial distance and thus the interaction between active sites. Remarkably, the PtSAC with improved active site interaction exhibited significantly enhanced intrinsic activity towards acidic hydrogen evolution (e.g., a high turnover frequency of 8.01 H2 s−1 at 20 mV), surpassing commercial Pt/C and other reported outstanding catalysts. Theoretical calculations further revealed that the increasing interaction between single atom active sites can largely modify their electronic configurations and result in more favored hydrogen adsorption/desorption behaviors, which is responsible for the enhanced intrinsic activity towards hydrogen evolution catalysis.