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

摘要

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 (similar to 400 ppm) with injected H2O2 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 H2O2 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 NO3-, which was confirmed by Ion Chromatography. In addition, the mechanism of PCO is also discussed in detail. The results indicate that O-center dot(2)- plays a leading role in the process of PCO of NO. (C) 2017 Elsevier B.V. All rights reserved.