G C3N4 was supported on the surface of foamed ceramic, and the g-C3N4@foamed ceramic was packed in the photocatalytic reactor in a layered manner. Effects of urea and H2O2 concentration on NO conversion were investigated. Pulse experiments were carried out to investigate the change of NO conversion with time under different concentrations of H2O2. The contribution of each route that NO converted and the selectivities of products were calculated. Results showed that the photo-reduction of NO accounted for 2%, and the photo-oxidation of NO accounted for 14%, and the rest was absorbed by the humidifier. Products include ammonia (NH+ 4-N), nitrogen (N-2), nitrite (NO- 2-N) and nitrate (NO- 3-N), of which N-2 accounted for 9%. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.