Tunable Pyridyl-Based Conjugated Microporous Polymers for Visible Light-Driven Hydrogen Evolution

Conjugated microporous polymers (CMPs) are promising light harvesters for photocatalytic H2 evolution because they are simple to prepare with various band gaps. To achieve CMPs displaying high photocatalytic performance, appropriate building blocks must be chosen. We prepared four kinds of triphenylpyridine-based CMPs (TPP-CMPs) through reactions with multibrominated monomers having different geometries [1,3,6,8-tetrabromopyrene (pyrene-4Br), pyridine (TPP-3Br), and 1,2,4,5-tetrabromobenzene (BZ-4Br), TPP, and TPP-benzene (BZ) CMPs, respectively]. This strategy allowed effective synthetic regulation of electron enrichment, porosities, and optoelectronic properties of the TPP-CMPs. The surface areas of the TPP-CMPs were high, up to 1370 m2 g-1, and had a high thermal stability. TPP-Py CMP displayed the highest photocatalytic performance with a H2 production rate of 18 100 mu mol g-1 h-1 under irradiation with visible light. Moreover, we achieved apparent quantum yields as high as 22.97% at 420 nm, comparable with those of most other CMPs reported previously.

Automated summary

Conjugated microporous polymers (CMPs) are promising light harvesters for photocatalytic H2 evolution due to their simple preparation and various band gaps. By selecting different geometries of multibrominated monomers, four triphenylpyridine-based CMPs were synthesized with controlled electron enrichment, porosities, and optoelectronic properties. Among them, TPP-Py CMP exhibited the highest photocatalytic performance under visible light irradiation, with high surface area, thermal stability, hydrogen production rate, and quantum yield.