Facial synthesis of sheet-like carbon nitride from preorganized hydrogen bonded supramolecular precursors and its high efficient photocatalytic oxidation of gas-phase NO

Abstract

Abstract In this paper, a series of sheet-like carbon nitride (CN) semiconductor photocatalysts was synthesized by facial supramolecular method using cyanuric acid (C), melamine (M) and 2,4-diamino-6-methyl-1,3,5-triazine (Mm) as precursors. It is the first report where the latter monomer was used in such synthetic route. The prepared C-M-Mm CNs possess higher specific surface areas, stronger light absorption as well as lower recombination rate of photogenerated electron-hole pairs in comparison with bulk CN. They were used on the photocatalytic oxidation (PCO) of NO (∼ 400 ppm) with injected H 2 O 2 solution (0.044 mL min −1 ) under simulated solar-light irradiation. The results indicate that the C-M-Mm CNs exhibit tremendous enhanced photocatalytic activity, wherein the C 1 -M 0 -Mm 1 CN possesses the highest photocatalytic activity (94.86%). The enhanced photocatalytic performance belongs to the synergic effect of large specific surface area, wide solar-light absorption edge and high separation and transfer efficiency of photogenerated electron-hole pairs. The presence of H 2 O 2 is also essential in the improvement of the photocatalytic efficiency via production of more active species. The main product in the PCO of NO is NO 3 − , which was confirmed by Ion Chromatography. In addition, the mechanism of PCO is also discussed in detail. The results indicate that O 2 − plays a leading role in the process of PCO of NO.