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

Abstract

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 H2 production. With optimal doping amount, Fe10/CTF‐1 exhibited a satisfying H2 production activity of 1460 μmol 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.

Hollow Covalent Organic Framework Cages with Zn Ion‐Implantation Promoting Photocatalytic H2 Evolution

“…In comparison with pure TpPa and TpBD, Zn ion implantation made TpPa and TpBD with a widened bandgap, while Co ion made TpPa with a narrowed bandgap, showing the feasibility of tuning the electronic structure of COFs through implantation of metal ions. [24] Encouraged by the above results, photocatalytic H 2 production experiments by using TpPa, TpBD, Zn@H-TpPa, Co@H-TpPa, Zn@H-TpBD as photocatalysts were performed under a visible light irradiation with Pt as a cocatalyst. Zn@H-TpPa and Zn@H-TpBD exhibited remarkably enhanced H 2 evolution efficiency when compared with TpPa and TpBD, respectively (Figure 4a).…”

Graphitic Aza‐Fused π‐Conjugated Networks: Construction, Engineering, and Task‐Specific Applications

“…The resultant rate was 1460 µmol h −1 g −1 , 28‐fold higher than the pure CTF‐1. [ 192 ] Enhancement of the photocatalytic activity of CTFs in HER under visible‐light irradiation could be achieved by sulfur‐doping approach. [ 193 ] The activity of CTFs toward photocatalytic H 2 evolution could be enhanced by phosphorus doping with red phosphorus as the source, achieving modification over the generation, separation, and migration of photoinduced electron–hole pairs and H 2 production rate 4.5 times as high as the original CTF‐1.…”

Modification of Covalent Triazine-Based Frameworks for Photocatalytic Hydrogen Generation

“…Fe 3+ ions were also claimed to be doped into the CTF molecule structure. With the increase in Fe amount, the valence band position shifted more negatively, resulting in a 30 times improvement in the hydrogen generation rate than the bare sample of 30 µmol h −1 (>420 nm) [ 50 ]. Protonating CTFs by acid was a strategy to enhance hydrophilicity.…”