Xinghao Zhang, Xiaomeng Guo, Hui Jiao, Yutong Wang, Hanxi Li, Xin Lian, Haichao Wang, Yinqiang Zhang, Xiaoxia Chang, Jijie Zhang, Xian‐He Bu
Modulating the coordination geometry of single atoms (SAs) is crucial for overcoming the limitations in catalytic activity. This study aims to construct a clear relationship between the coordination geometry of Pt SAs and their catalytic activity to guide the synthesis of targeted high-activity SA catalysts. An interesting atomic-level predesign strategy for SA carriers is proposed, enabling precise atomic regulation of N 2c coordination sites. Seven distinct SA carriers were synthesized: pristine CN, N v -CN (1, 2, 3) with N 2c vacancies and O d -CN (1, 2, 3), in which N 2c sites are substituted by oxygen doping, thereby achieving the controlled synthesis of four Pt coordination geometries: Pt–N 4 in pristine CN, Pt–N 2 Cl 4 (reconstructed to Pt–N 2 ) in N v -CN, and Pt–N 3 O in O d -CN. Among these, O d -CN–Pt exhibited exceptional photocatalytic hydrogen evolution performance (66.4 mmol g –1 h –1 ), which is 3.75 and 2.7 times higher than that of CN–Pt and N v -CN–Pt, respectively. By combining in-situ KPFM-SPV, X-ray photoelectron spectroscopy, femtosecond transient absorption, and density functional theory calculations, a volcano-type relationship model was established between activity and three descriptors Bader charge, Pt 5d intensity, and Δ E (from PDOS to the Fermi level)─to elucidate the correlation between the coordination geometry and catalytic activity of SA-based catalysts. Such a descriptor may guide the predesign of high-performance SA catalysts.