Modification of Covalent Triazine-Based Frameworks for Photocatalytic Hydrogen Generation

Abstract

The conversion of solar energy and water to hydrogen via semiconductor photocatalysts is one of the efficient strategies to mitigate the energy and environmental crisis. Conjugated polymeric photocatalysts have advantages over their inorganic counterparts. Their molecular structures, band structures, and electronic properties are easily tunable through molecular engineering to extend their spectral response ranges, improve their quantum efficiencies, and enhance their hydrogen evolution rates. In particular, covalent triazine-based frameworks (CTFs) present a strong potential for solar-driven hydrogen generation due to their large continuous π-conjugated structure, high thermal and chemical stability, and efficient charge transfer and separation capability. Herein, synthesis strategies, functional optimization, and applications in the photocatalytic hydrogen evolution of CTFs since the first investigation are reviewed. Finally, the challenges of hydrogen generation for CTFs are summarized, and the direction of material modifications is proposed.

Arylboron functional covalent organic frameworks for synergistic photocatalytic hydrogen evolution

“…6,7 To solve these problems, Yanagida 8 and Wang 1 successively reported organic materials poly( p -phenylene) and carbon nitride (g-C 3 N 4 ) as photocatalysts and verified their photocatalytic HER ability, respectively. Subsequently, more organic polymers were explored as photocatalysts for the HER, including the carbon nitride (g-C 3 N 4 ) family, 1 conjugated microporous polymers (CMPs), 9 covalent triazine-based frameworks (CTFs), 10 conjugated linear polymers (CLPs), 11 and others. 12,13 However, photocatalytic HER is a multi-step continuous process that requires comprehensive regulation of molecular mechanisms with respect to the light-harvesting capability, band gap, and interface to reduce photo-generated electron/hole recombination.…”

Strategic design of covalent organic frameworks (COFs) for photocatalytic hydrogen generation

“…In addition, covalent triazine frameworks (CTFs) have also been applied for efficient and durable water-splitting performance (see below). 42,102…”

Recent Progress in Conjugated Polymers-Based Donor–Acceptor Semiconductor Materials for Photocatalytic Hydrogen Evolution from Water Splitting

“…The basic skeleton of covalent triazine-based frameworks (CTFs) is composed of alternating triazines and phenyl groups [92]. Compared with other organic semiconductor photocatalysts, CTFs have a larger continuous π-conjugated structure, which enables rapid charge transfer.…”