Vinylene-linked covalent organic frameworks with manipulated electronic structures for efficient solar-driven photocatalytic hydrogen production

Recent advances on covalent organic frameworks (COFs) as photocatalysts: different strategies for enhancing hydrogen generation

“…Chen and co-workers prepared three D–A type COFs to explore the influence of weak donors on photocatalytic HER ability by varying donor monomers from phenyl to 2,5-dimethylbenzene and 3,3′-dimethyl-1,1′-biphenyl in the skeletons. 56 The results revealed that the D–A interaction was enhanced with an increase in the donor conjugation effect, with TM-DMA-COF exhibiting the best HER rate of up to 4300 μmol g −1 h −1 .…”

“…Adopting this strategy, a variety of COFs have been prepared. 53–68 For example, Yang et al designed PETZ-COF via the solvothermal reaction of electron-donating 4PE-4NH 2 and electron-deficient TZTZ-2BA for photocatalytic H 2 generation. As a comparison, a COF (PEBP-COF) without D–A moieties was also constructed using 4PE-4NH 2 to react with BP-2BA (Fig.…”

Inducing local charge polarization by constructing isomeric covalent organic frameworks with different orientations of imine bonds for enhancing photocatalytic hydrogen evolution

“…13,14 To address these issues, the construction of donor–acceptor (D–A) type COFs has been explored to enhance unit polarity and promote conjugation, thereby facilitating exciton dissociation and the separation of electron–hole pairs. 15–21 In the D–A system, excitons are typically generated at the donor moiety and transferred to the acceptor moiety at the D–A interface, where they dissociate into electron–hole pairs. 22–24 The chemical bond linkers represent the D–A interface of COFs to connect the donor and acceptor, where the dissociation of the excitons occurs.…”

Molecular Engineering in D-π-A-A-Type Conjugated Microporous Polymers for Boosting Photocatalytic Hydrogen Evolution

“…Different from inorganic photocatalysts, organic photocatalysts have unique superiorities, such as an earth-abundant natural resource, flexible structure design, and easily tuned energy band structures. In the past years, organic semiconductive photocatalysts with a conjugated molecular skeleton have been broadly exploited for hydrogen evolution, such as organic small molecules, − graphitic carbon nitrides, − crystalline porous organic polymers, − and amorphous conjugated microporous polymers (CMPs). − Among them, CMP photocatalysts manifest the advantages for hydrogen generation because of the high contact area between the catalyst surface and reaction medium, high structural stability, and three-dimensional extended conjugated polymer skeletons, which are conducive to a photocatalytic hydrogen production reaction. Impressively, some attractive progress has been made on CMP photocatalysts for hydrogen production under natural sunlight outdoor. , …”