Out of the misty forest of MOF composite heterojunctions: A new cognitive guide

Environmental remediation and energy shortage have always been problems that plague the world. Photocatalysis and photo-electrocatalysis are effective strategies to solve the environmental pollution and energy crisis. Compared with traditional inorganic catalysts, metal-organic frameworks (MOFs) have the characteristics of high porosity, large specific surface area and tunable structure, etc. When MOF cooperates with other materials to form heterojunctions, the interfacial energy barrier is reduced, the separation efficiency of electron-hole pairs (EHPs) is improved and the catalytic efficiency is enhanced. Therefore, this review innovatively proposes a collaborative material classification method, categorizing MOF heterojunctions into MOF-on-MOF, MOF-on-COF, MOF-on‑carbon, MOF-QD, and MOF-Mxene and other types. Thereby, a new cognitive guide is constructed, providing effective guidance for readers to quickly establish a preliminary understanding. Subsequently, the synthesis methods and action mechanisms of MOF composite heterojunctions are comprehensively analyzed and discussed, providing ideas for preparing catalysts more suitable for biomedical applications. In addition, the principles of electrocatalysis, photocatalysis, and molecular simulation are expounded to guide researchers in analyzing, designing, and verifying new biological MOF heterojunctions. Meanwhile, the latest application progress of MOF heterojunctions in various fields is comprehensively discussed, emphasizing their huge potential in photo-electrocatalysis, antibacterial, cancer treatment, biosensing, and other fields. Finally, the challenges and prospects of MOF composite heterojunctions are presented. This review provides a comprehensive insight into heterojunctions with MOF as an essential material, aiming to pave the way for their application in biomedical fields.