Co‐Catalyst/Semiconductor Interface Coupling Design for Efficient Solar‐Driven Photocatalysis

ABSTRACT

Interfacial charge transfer at co‐catalyst/semiconductor heterojunctions critically determines photocatalytic efficiency, yet existing reviews mainly summarize individual interface engineering strategies without establishing a unified principle that correlates interfacial interaction with charge‐transfer behavior and photocatalytic functionality. Here, we propose interfacial coupling strength as a unified descriptor that fundamentally governs interfacial charge‐transfer behavior, electronic structure evolution, and photocatalytic performance. Based on this concept, this review establishes a framework‐oriented perspective that reformulates diverse interface engineering strategies into coupling‐strength‐regulated design paradigms. Unlike conventional classification‐based reviews, this work emphasizes the intrinsic relationship between coupling strength, interfacial electronic reconstruction, charge‐transfer pathways, and catalytic functionality, thereby providing a predictive framework for rational interface design. Within this framework, interface engineering strategies are reformulated into two design paradigms: (i) indirect coupling through interfacial mediators, which enables continuous tuning within the intermediate coupling regime, and (ii) direct interface engineering, spanning weakly coupled van der Waals heterojunctions to strongly bonded interfaces with covalent, ionic, or metallic interactions. More importantly, this framework establishes a coupling‐strength‐guided design principle, where targeted photocatalytic functionality can be achieved by positioning interfaces within specific coupling regimes. Weak coupling preserves intrinsic electronic structures but limits charge transfer; intermediate coupling provides tunability for balancing carrier dynamics; and strong coupling enables rapid, directional charge transport, and enhanced stability. This review provides a coupling‐strength‐guided theoretical framework that bridges interface structure, electronic interaction, and photocatalytic functionality, offering new insights for the rational design of next‐generation photocatalytic systems.