Study on the effective removal of NO by light-driven N-BiOCl

Abstract

In this paper, an N-doped BiOCl photocatalyst was prepared and systematically characterized. The results showed that N doping does not change the crystal phase of BiOCl but changes the surface morphology of BiOCl nanosheets and increases specific surface area. N-doped BiOCl broadens the light absorption region, narrows the band gap and promotes the separation of the photoexcited carriers. N could be adsorbed on the Bi or to replace Cl atom in the BiOCl lattice, causing the generation of intermediate energy levels in the band gap of N-BiOCl including N 2p-Cl 2p hybrid states, N 2p-O 2p hybrid states or N 2p state. N-BiOCl achieves about 60% removal efficiency of NO under all-light irradiation and exhibits favorable stability and recyclability. The presence of some H2O in the reaction system promotes the photodegradation of NO, while O2 greatly affects the efficiency of NO removal. Moreover, N doping promotes the formation of •O2− and •OH on N-BiOCl photocatalyst under all-light irradiation, resulting in the enhancement of photocatalytic oxidation of NO to NO3–. NO could be adsorbed on the surface of N-BiOCl or oxidized into NO2– under darkness and further oxidized into NO3– under all-light irradiation. However, the accumulation of the final product on the catalyst surface results in a decrease in photoactivity.