Hexaazatriphenylene doped carbon nitrides-biomimetic photocatalyst with superior oxidation power

Abstract

Pyrazine rings are a fundamental part of folic acid and flavine - cofactors that participate in natural electron transfer processes. Electron deficient carbon nitrides, more specifically poly(heptazine imides) (PHI), emulating the structure of these pyrazine based cofactors were synthesized polymerizing 3-amino-1,2,4-triazole-5-thiol with hexaazatriphenylene-hexacarbonitrile or hexaazatriphenylene-hexaamide at 550 degrees C in the eutectic mixture of KCl/LiCl. The role of hexaazatriphenylene units is 1) to create electron deficient acceptor sites in the structure of semiconductor; 2) widen the spectral coverage up to near infrared region. The significantly increased oxidative power of such doped PHI was demonstrated by running oxygen evolution from water, 0.59 mu mol h(-1), under visible light irradiation in the absence of any metal co-catalyst. (C) 2017 Elsevier B.V. All rights reserved.