Band structure tunable synthesis of photocatalytic porous aromatic frameworks via Scholl reaction

Porous aromatic framework (PAF) materials with π-π conjugation system based on Scholl reaction were found to exhibit satisfying photocatalytic performance, that can successfully degrade Rhodamine B (RhB) and colorless phenol. By selecting different multiple-phenyl building blocks, six kinds of PAF materials named as P-BP materials were successfully constructed by Scholl reaction, which exhibit not only photocatalytic ability, but also moderate specific surface areas, wide solar spectrum coverage, and good thermal and chemical stabilities. Depending on their different building block selections, the photocatalytic performance can be adjusted. The P-BP-DPA was found to exhibit the highest photocatalytic performance with 100% and 50% degradation rate for RhB and phenol in 300 min, respectively. Free radical trapping experiments showed that the photocatalytic activity originated from the strong oxidation capability of photogenerated holes. The band structure of such group of materials can be readily adjusted. With different monomers, their band gaps can be tuned from 1.87 to 2.36 eV, and their valence band positions were adjusted from 1.93 to 3.44 eV (vs NHE).