Innovative strategies in noble and earth abundant metal single-atom-based photocatalysts for hydrogen production

This review presents a comprehensive overview of noble (Pt, Pd, Ag, Au, Ru, and Rh) and earth abundant metals (Co, Cu, Ni, Fe, and Mo) single-atom-based photocatalysts (SACs) for hydrogen (H 2 ) production. We first highlight the fundamental of SACs followed by rational design strategies to achieve atomic-level distribution, and increase the density of active sites. Then, thoroughly summarize the enhanced H 2 production activity of noble and earth abundant metal-based SACs. Moreover, insights into the charge transfer mechanisms, such as charge separation, transfer, and spatially defined electron delocalization to unravel the structure-activity relationship and coordination-dependent catalytic performance. Finally, we discuss recent challenges and prospects for designing highly effective SACs. Overall, this review provides a valuable guidance by highlighting fundamental principles of SACs, performance assessment, and mechanistic insights toward practical solar-to-H 2 conversion.