Xu Zhang, Qixin Zhou, Chen Li, Hui Su, Taoran Chen, Peixin CUI, Chaogang Ban, Ying Tao, Jiaxing Wang, Yuheng Jiang, Lingyue Liu, Zhenyuan Teng, Zhanxi Fan, Yulin Zhao, Kun Zheng, Jie Ding, Chenliang Su, Tierui Zhang, Bin Liu
The thermodynamic and kinetic mismatch between oxidative and reductive half-reactions represents a central barrier in photocatalysis, largely due to the absence of well-defined and functionally differentiated active sites. Herein, we construct Co and Pt redox dual-site catalysts (CoPt RDSCs), featuring nonbonded yet spatially close single atoms anchored on carbon nitride for H 2 O 2 photosynthesis, thereby enabling site-specific utilization of photogenerated holes and electrons. The Co sites act as the hole centers that drive the four-electron water oxidation reaction, whereas the Pt sites serve as the electron centers that catalyze the two-electron oxygen reduction reaction, each lowering the thermodynamic barrier of its respective half-reaction. Crucially, the proximity of these electronically decoupled sites enables the directed migration of the oxidation products (O 2 and H + ) generated at Co sites to neighboring Pt sites, establishing an internal redox-coupling pathway that accelerates the overall reaction kinetics. Multidimensional in situ spectroscopy, transient photodynamics, and theoretical analyses confirm that each half-reaction proceeds on the designated site independently yet synergistically. Consequently, the CoPt RDSCs achieve a 19.33% apparent quantum efficiency at 420 nm and a 1.46% solar-to-chemical conversion efficiency for H 2 O 2 synthesis in pure water, outperforming most of the reported photocatalysts under comparable conditions. Spatial engineering of redox active sites establishes a general design principle for constructing high-performance photocatalysts capable of coordinating oxidative and reductive transformations.