Doping effect of metalloid group in graphitic carbon nitride molecular structure for significantly improved photocatalytic hydrogen production and photoelectric performance

It is a considerable research focus to introduce a new conjugate structure into the graphitic carbon nitride (g-C3N4) molecule by polymerization to improve the photocatalytic and photoelectrochemical performance. Herein, the 1,4-cyclohexadiene (CHD) group-doped g-C3N4 (CHD-g-C3N4) nanosheet photocatalyst is prepared by a simple thermal polymerization, which dramatically improves the photocatalytic H-2 production and photoelectrochemical performance. Surprisingly, the optimal H-2 production rate and the photocurrent density of CHD-g-C3N4 reaches up to 522.0 mmol h(-1) g(-1) and 31.19 mu A cm(-2), which is 6.29 and 6.96 times higher than that of pure g-C3N4, respectively. The high-efficiency and stable photocatalytic H-2 production and photoelectrochemical performance of CHD-gC(3)N(4) originate from the doping effect of conjugated groups in g-C3N4 molecule, which extends the pi-conjugated system to accelerate electron mobility. This work indicates that the introduction of metalloid groups with conjugation effect is of great significance for improving photocatalytic and photoelectric performance, and provides a new idea for the non-metallic modification of g-C3N4 as a highly active catalyst. (C) 2020 Published by Elsevier Ltd.