Preparation of tellurium doped graphitic carbon nitride and its visible-light photocatalytic performance on nitrogen fixation

Tellurium doped graphitic carbon nitride (TeCN) photocatalyst was synthesized by the combination of hydrothermal treatment and copolymerization of melamine and tellurium powder. With Te doping, 1% TeCN exhibits a high nitrogen fixation rate under visible light irradiation, which is 7.2 times compared to that of graphitic carbon nitride (CN). The markedly higher activity of 1% TeCN is attributed to the better chemical adsorption of N2, enhanced separation efficiency of charge carriers and higher CB potential. Notably, a new midgap states induced by Te doping also contributes to the improved activity of nitrogen fixation. Besides, valence state changes between Te6+, Te4+ and Te° in 1% TeCN further promoted the nitrogen fixation activity. This study demonstrates that the modification of g-C3N4 by Te is an effective way to improve the photocatalytic nitrogen fixation effect of the photocatalyst.