P-doped melon-carbon nitride for efficient photocatalytic HO production.

Melon-based carbon nitride (CN) is a semiconductor photocatalyst with a conduction band position suitable for photocatalytic HO production. However, the thermodynamic inability to adsorb O molecules greatly limits its photocatalytic efficiency for HO production. In this paper, P-doped CN with good performance for HO production was synthesized by a simple one-step calcination method. The experimental results show that when the doping amount of P is about 9.0 wt% of CN, the yield of HO can reach 12990 μM/h/g, which is about 6.6 times as that of pure CN. The mechanism of HO production over P-CN was firstly revealed by using the density functional theory calculations based on the melon crystal structure of carbon nitride. The results show that P-doping is easier to the strong thermodynamic adsorption of O on CN, which is more beneficial to the formation of intermediate products. Further experimental results show that the substitution of C in CN by P-doping suppresses the electron and hole recombination, and therefore promoting the photocatalytic performance of P-doped CN.