Band Gap Tuning of Covalent Triazine-Based Frameworks through Iron Doping for Visible-Light-Driven Photocatalytic Hydrogen Evolution

Photocatalytic hydrogen energy production through water splitting paves a promising pathway for alleviating the increasingly severe energy crisis. Seeking affordable, highly active, and stable photocatalysts is crucial to access the technology in a sustainable manner. Herein, a trivalent iron-doped covalent triazine-based framework (CTF-1) was elaborately designed in this study to finely tune the band structure and photocatalytic activity of CTF-1 for H-2 production. With optimal doping amount, Fe-10/CTF-1 exhibited a satisfying H-2 production activity of 1460 mu mol h(-1) g(-1), corresponding to 28-fold enhancement compared with pure CTF-1. The Fe3+ doping is responsible for a remarkedly broadened visible-light adsorption range, improved reduction ability and inhibited electron-hole recombination of CTF-1. Specifically, the doped Fe3+ could serve as photocatalytically active center and "electron relay" to accelerate charge separation and transformation. This study offers a feasible strategy to validly design and synthesize CTF-based photocatalytic materials to efficiently utilize solar energy.