Enhancement of degradation for nitrogen doped zinc oxide to degrade methylene blue

Abstract

Nitrogen doped zinc oxide (N-doped ZnO) photocatalyst has been synthesized by sol-gel method and the mechanism has been investigated by the first principle simulation. Experimental results show that N-doping into ZnO can enhance the photocatalytic activity of methylene blue (MB) dye in ultraviolet (UV) and visible light, which due to its smaller band gap and more oxygen vacancies on surface of N-doped ZnO. First principle calculations indicated that N atoms occupying oxygen vacancies reduce the band gap of ZnO, where the 2p electrons of N produce a local state near the valence band of ZnO, that makes the photogenerated electron easier to be transferred from valence band to hole to facilitate the generation of photocatalysis. N-doped ZnO as an effective photocatalyst has good features for photocatalytic degradation of organic pollutants and the treatment of wastewater.