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Semiconductor-based photocatalyst, whose efficiency distinctly hinges on the separation of photoinduced charge transfer within the interface of bulk structure, has incurred some intractable issues due to the existing energy barrier. Regulating the structure of MOF reasonably would feature an accelerated charge separation, and an effective utilization of photogenerated charges. Herein, a new type of MOF with both interior linker and metal valence modulation (m-MIL-101–1.0) is reported to boost photocatalytic activity owing to the formed charge migration pathway. At first, we introduced defective sites via CTAB, which acted as exposed sites for further reduction reaction. Then, NaBH 4 was used to achieve metal valence regulation. Benefiting from the unique structure, the Fe3+/Fe2+ redox center was considered as a driving force to facilitate the charge transfer. It is properly considered that the activity improvement is attributed to the synergistic effect of both internal and external charge transfer channels. As a result, such m-MIL-101–1.0 has a higher activity than that of MIL-101 for photocatalytic degradation of tetracycline in water. We envision this interior configuration would be an ideal paradigm for tuning the activity of MOFs and extending the boundaries of MOF-based photocatalysts. A Fe3+/Fe2+ mediated distinct charge transfer pathway in MOF, rather than poor charge transfer within bulk or interface, works as an efficient photocatalyst. [Display omitted] • The formation of Fe2+/Fe3+ via one-step reduction for coordination-ameliorated MOF was reported. • The poor bulk or interface charge transfer is alleviated in this system. • Metal center mediated pathway averts the low separation efficiency of charge carriers. • The photodegradation efficiency of TC reaches 86.1% in an hour. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterojunctions are emerging as prospective candidates for the degradation of POPs. • The basic principles and the fabrication strategies were systematically discussed. • Recent heterojunction photodegradation of POPs and the mechanisms were appraised. • Challenges and perspectives facing heterojunction were insightfully elucidated. Photocatalysis has attracted a broad range of attention because of its ability of efficient solar energy utilization for environmental governance. Hence, abundant photocatalysts have been investigated continuously to meet the requirement of energy-supply issues. However, engineering photocatalysts with strong visible light-harvesting ability, efficient charge separation, and superior stability is imminently desired due to the low efficiency of photocatalytic reactions with an individual photocatalyst. Particularly the fabrication of heterostructured photocatalysts have conquered the aforementioned bottlenecks and displayed great potential in the field of contaminants degradation. Herein, we summarized the recent significant progress on the design of different heterostructured photocatalysts and their wide applications in persistent organic pollutants (POPs) degradation is highlighted. We firstly introduce the representative synthetic tactics, the charge transfer mechanism, and the categories. Thereafter we outline state-of-the-art heterostructured photocatalysts for the degradation of different types of POPs, in which the improvement of primary focus on the reason why the photocatalytic activity was high. Additionally, we proposed the ongoing challenges and perspectives of heterojunction photocatalytic systems. [ABSTRACT FROM AUTHOR]