Microwave assisted rapid synthesis of TiO NFs@COF S-scheme heterojunction photocatalyst for highly efficient photocatalytic hydrogen evolution.

The S-scheme heterojunctions composed of covalent organic frameworks (COFs) and inorganic semiconductors have attracted considerable attention for photocatalytic hydrogen evolution. However, the rapid preparation of COFs-based S-scheme heterojunctions with a robust interface remains a significant challenge. Herein, a novel TiO nanofibers (NFs)@COF S-scheme heterojunction is synthesized via a microwave heating method. The prepared sample exhibited a large specific surface area (S), a strong contact interface, and excellent photocatalytic hydrogen production performance. The optimal composite (CT180) achieved a hydrogen evolution rate of 58.30 mmol g h, which is 21.35 and 4.17 times higher than those of pure TiO NFs and benzimidazole-based covalent organic framework (PABZ-TP-COF), respectively, surpassing many well-known heterojunction photocatalysts. Furthermore, the S-scheme charge transfer mechanism in the TiO NFs@COF heterojunction photocatalyst was confirmed through in situ XPS, EPR, and DFT calculations. This work provides new insights into the rapid fabrication of inorganic-organic S-scheme heterojunction photocatalyst.