In‐Situ Anchoring of Co Single‐Atom Synergistically with Cd Vacancy of Cadmium Sulfide for Boosting Asymmetric Charge Distribution and Photocatalytic Hydrogen Evolution

In the context of reshaping the energy pattern, designing and synthesizing high-performance noble metal-free photocatalysts with ultra-high atomic utilization for hydrogen evolution reaction (HER) still remains a challenge. In a streamlined synthesis process, in-situ single atom anchoring is performed in parallel with HER by irradiating a precursory defect-state CdS/Co suspension (Co-DCdS-Ss) system under simulated sunlight and the in-situ synthesizing single-atom Co photocatalyst (Co5:DCdS) exhibits further improved catalytic performance (60.10 mmol g^-1 h^-1) compared with Co-DCdS-Ss (18.09 mmol g^-1 h^-1), reaching an apparent quantum yield of 57.6% at 500 nm and a solar-chemical energy conversion efficiency (SCC) of 6.26% at AM 1.5G. In-depth characterization tests and density functional theory (DFT) calculations prove that the anchoring of Co single atom deepens the asymmetric charge distribution of the two-coordination S atom adjacent to the cadmium vacancy (V_Cd). The synergy between electron delocalization V_Cd and Co single atom on the catalyst surface is constructed, which bifunctional sites responsible for boosting water adsorption-dissociation and hydrogen evolution. This study advances the understanding of the underlying mechanisms of synergy between surface defects and metal single atoms and opens a new horizon for the development of advanced materials in the field of photocatalysis.