Dedicated to Professor Matthias Beller on the occasion of his 60th birthday.

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.

Regulating the coordination environment of single‐atom sites is of high necessity to promote the catalytic performances of the photocatalysts. Herein, the preparation of atomically dispersed Co‐Ag dual‐metal sites anchored on P‐doped carbon nitride (Co1Ag1‐PCN) via supramolecular and solvothermal approaches is reported, which demonstrates desirable performance for photocatalytic H2 evolution from water splitting. The optimal Co1Ag1‐PCN catalyst achieves a remarkable hydrogen production rate of 1190 µmol g−1 h−1 with an apparent quantum yield (AQY) of 1.49% at 365 nm, superior to most of the newly reported metal‐N‐coordinated photocatalysts. Systematic experimental characterizations and density functional theoretic studies attribute the enhanced photocatalytic activity to the synergistic effect of Co‐Ag dual sites with exclusive coordination configuration of Co‐N6 and Ag‐N2C2, which enhances the charge density and promotes oriented electrons transport to the metal centers with reduced free energy barriers by facilitating the formation of H* intermediates as the key step in hydrogen evolution. This study reveals a versatile strategy to tailor the electronic structures of dual‐metal sites with synergies by engineering the neighboring coordination environment.

Transfer hydrogenation using liquid hydrogen carriers as the direct proton sources under mild conditions has received extensive attention in the research area of organic synthesis. The emerging photocatalytic water-donating transfer hydrogenation (PWDTH) is a promising alternative over the conventional hydrogenation technology due to the advantages of being eco-friendly. This paper focuses on the recent advances in the rising and rapidly developing field of PWDTH reactions, devoted to elucidating the mechanism of the hydrogen transfer process and rationalizing the design principles of efficient photocatalysts. Finally, the current challenges and future opportunities are described.

Dedicated to Professor Matthias Beller on the occasion of his 60th birthday.