Synergistic Promotion of Single-Atom Co Surrounding a PtCo Alloy Based on a g-C₃N₄Nanosheet for Overall Water Splitting

Atomically dispersed catalysts with maximum efficiencies for atom utilization have emerged as a frontier in the catalytic field. However, single-component monatomic catalysts are rarely reported for the overall photocatalytic water splitting reaction (OWS). Herein, a two-component synergistic photocatalyst was designed that contained a dispersion of single-atom Co (CoSAs) centers and PtCo alloy nanoparticles (Nps), which were supported over C3N4 nanosheets. Among these components, CoSAs centers act as highly active sites for the hydrogen evolution reaction (HER), and PtCo alloys act as highly active sites for the oxygen evolution reaction (OER). A synergistic effect between them occurs when the two different reactive centers are combined, indicating that there may be a spillover phenomenon of protons or hydroxyl groups between the CoSAs centers and PtCo alloy NPs. The synergistic promotion of CoSAs centers and PtCo alloys bridges the gap between achieving maximum atom utilization and optimal bifunctional activities for OWS reactions. This combination provides a promising model for the development of OWS by atomically dispersed catalysts.