Interfacial Charge Transfer in ZnO/COF S‐Scheme Photocatalyst via Zn <i>─</i> N Bond

Abstract

Abstract Photocatalysis is a promising solution to global energy shortage and environmental problems. Inspired by photosynthesis, multicomponent heterostructured photocatalysts are extensively investigated, and step‐scheme (S‐scheme) heterojunction has emerged as the theoretical basis for delineating charge transfer processes in predominant heterostructured photocatalysts. However, the specific charge transfer pathway across an S‐scheme heterojunction remains elusive from an atomic/molecular perspective. Herein, it is demonstrated that in S‐scheme heterojunction photocatalysts composed of imine‐based covalent organic frameworks and nanostructured zinc oxide, interfacial Zn ─ N bonds are formed between the two components and play critical roles as a charge transfer gateway in the S‐scheme heterojunction, based on theoretical calculations, X‐ray absorption spectroscopy, and X‐ray photoelectron spectroscopy. Moreover, mechanisms for enhanced charge transfer across the S‐scheme heterojunction are elucidated using femtosecond transient absorption spectroscopy. This work provides new insights into molecular‐level understanding of charge transfer mechanisms in S‐scheme heterojunction photocatalysts for promoting energy and environmental applications of artificial photosynthesis.