Recently, Prof. Deng Weiqiao's team from the Institute of Frontier and Interdisciplinary science of Shandong University made new progress in the field of covalent organic framework for photocatalytic hydrogen production, and the research paper entitled "Heterogenization of Salen Metal Molecular Catalysts in Covalent Organic Frameworks for Photocatalytic Hydrogen Evolution" was published in Angew. Chem. Int. Ed.. Shandong University is the first author institute of this paper.

Photocatalytic water splitting has been considered a promising way to obtain clean hydrogen energy. In recent years, porous crystalline covalent organic frameworks (COFs) as efficient photocatalysts have attracted extensive attention. Featuring rich channels, large specific surface area, and adjustable structural components, porous covalent organic frameworks provide a platform for the study of photocatalytic performance and mechanism. In the research of covalent organic framework photocatalytic hydrogen production, constructing effective catalytic active sites is an important way to improve catalytic performance. In this respect, Prof. Deng Weiqiao's research team proposed a new strategy of heterogenization of homogeneous molecular catalyst for the construction of covalent organic framework photocatalyst, which involves periodically arranged catalytic active sites in the frame structure. Specifically, the molecular catalyst Salen metal and light harvesting group pyrene were connected through covalent bonding to form the repeating unit structure of covalent organic framework, and a series of crystalline Salen-metal covalent organic framework materials (Salen-COF) containing different metal centers were successfully prepared. The light absorber pyrene in Salen COF is closely connected with Salen-metal catalytic active center, meanwhile, a conjugated system is formed inside the material, which promotes the transfer and utilization of photogenerated charges. As a result, Co/Zn-Salen-COF showed a photocatalytic hydrogen evolution activity of 1378 μmol g^-1h^-1, which is superior to the previously reported non-noble metal-based COFs photocatalysts. This work provides a new idea for designing efficient active sites of covalent organic framework photocatalyst materials.

Doctoral students Zhou Wei and Deng Qiwen from the Institute of Frontier and Interdisciplinary science of Shandong University are co-first authors of this paper, and assistant professor Li Zhen and Professor Deng Weiqiao are co-corresponding authors. This research was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province and the Program of Young Scholars Future Program of Shandong University.

Link to this paper:https://onlinelibrary.wiley.com/doi/abs/10.1002/ange.202214143