Highly efficient simulated solar-light photocatalytic oxidation of gaseous NO with porous carbon nitride from copolymerization with thymine and mechanistic analysis

Abstract

We synthesized novel and efficient porous carbon nitride (CN) photocatalysts by facial supramolecular approach using cyanuric acid (C), melamine (M) and thymine (T) as starting material. The T-modified CNs display excellent photophysical and photochemical properties: high specific surface area, strong light adsorption as well as low recombination rate of photoinduced electron–hole pairs. They exhibit tremendous enhanced photocatalytic activity on photocatalytic oxidation (PCO) of NO (∼400 ppm) under simulated solar-light irradiation, wherein the CM + 2.5 mol%-T possesses the highest photoactivity (93.3% in 40 min). The enhanced photocatalytic performance is ascribed to the synergic effect of large specific surface area and high separation and transfer efficiency of photoinduced electron–hole pairs. In the PCO of NO process, the main reaction product is NO₃⁻, which was confirmed by Ion Chromatography. In addition, the mechanism of PCO is also intuitively analyzed by trapping experiment. The results indicate that ˙O₂⁻ plays a leading role in the PCO of NO process.