Interfacial engineering in two-dimensional heterojunction photocatalysts

Photocatalysis is a prospective technology to solve the current environment and energy crisis. The exploitation of 2D photocatalyst materials is a research hotspot owing to their large specific surface area, intrinsic defect and abundant active sites. Particularly, 2D/2D heterojunctions own intimate interfaces with expanded contact areas, which is beneficial to facilitate the separation and transportation of electron-hole pairs and further improve the photocatalytic activity. Currently, most studies focus on the band structure alignment in the design of 2D/2D heterojunctions, while the importance of interfacial binding forces is often ignored. This review aims at highlighting the critical role of interfacial binding forces in the photocatalytic activity of 2D/2D heterojunctions for the first time. First, we classify the types of interfacial forces, including electrostatic force, van der Waals force, covalent bond, hydrogen bond. Then we summarize several typical strategies for constructing 2D/ 2D heterojunctions with corresponding structural features. Importantly, the photocatalytic mechanism is discussed based on interfacial composition, charge transfer path and modification of active sites, and various photocatalytic applications are summarized. Finally, we outline the challenges and future development in this prospective research field. It is expected to fill the existing knowledge gap on interfacial binding forces for designing efficient 2D/2D heterojunctions rationally. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.