ABSTRACT Overall water splitting is the most direct and scalable route to solar hydrogen production, yet only a limited number of photocatalysts can intrinsically drive this reaction because it requires redox‐neutral operation together with efficient charge separation and long‐term stability in water. Hetero‐structured photocatalysts provide a compelling path forward by integrating complementary half‐reactions while improving directional charge separation and preserving redox power. Here, we introduce a confinement‐enabled heterojunction strategy in which Zn─AgIn 5 S 8 quantum dots (ZAIS QDs) are in situ grown on nitrogen‐rich, highly porous, two‐dimensional aza‐fused covalent microporous polymer (aza‐CMP) nanosheets. The aza‐CMP nanosheets simultaneously stabilize ultrasmall QDs via confined nucleation and reconstruct the interface to generate a built‐in electric field and directional charge separation. Spectroscopic analyses provide direct evidence for an S‐scheme charge transfer pathway that retains strongly reducing electrons on ZAIS QDs for hydrogen evolution while accumulating highly oxidizing holes on aza‐CMP nanosheets for water oxidation. Consequently, the optimized heterostructure enables efficient overall water splitting and, with CoO x cocatalyst, achieves an apparent quantum efficiency (AQE) of 11.60% at 420 nm and a solar‐to‐hydrogen (STH) conversion efficiency of 0.62%. This study demonstrates that inorganic/organic S‐scheme photocatalysts are a promising platform for solar fuel synthesis.
Wei et al. (Wed,) studied this question.