Rational Design of Metal Oxide‐Based Heterostructure for Efficient Photocatalytic and Photoelectrochemical Systems

Solar‐driven photo‐to‐chemical conversion is an interesting approach for energy harvesting and storage with high sustainability. To achieve high photo‐to‐chemical conversion efficiency, it is important to develop cost‐effective and stable catalysts with high activity. Metal oxides provide an interesting platform for the development of efficient catalysts owing to their abundance, high stability, and tunable band edges. Their performance highly depends on the rational design of heterostructures with engineered electronic structures, modified charge migration behavior, tailored interfacial properties, and amplified electromagnetic fields. All these enable the achievement of efficient light harvesting, promoted charge separation and transport, and accelerated surface reactions. Herein, a recent study on rationally designed metal oxide heterostructures for enhancing photo‐to‐chemical energy conversion via photocatalytic and photoelectrochemical systems is reviewed. The approaches to enhance their conversion efficiency are as follows: 1) surface modification via loading of plasmonic metals and other photosensitizers; 2) surface regulation, including morphology, defect, and dopants; 3) interfacial assembly with metal oxides, other metal compounds, and metal‐free materials. Moreover, the underlying reaction mechanisms of metal oxide‐based heterostructures and how they affect the energy conversion efficiency are discussed. Finally, the challenges and perspectives on the development of metal oxide‐based heterostructures and associated photo‐to‐chemical devices are presented. Metal oxide‐based photocatalysts and photoelectrodes have gained considerable attention as promising candidates for photo‐to‐chemical energy conversion. Recent literature related to metal oxide‐based photocatalysts and photoanodes are highlighted with the underlying reaction mechanisms of metal oxide‐based heterostructures and how they affect the energy conversion efficiency. Rational designing of metal oxide‐based heterostructures provides an excellent platform for accelerating their practical applications.