Mechanisms research on visible irradiation degradation of organics by nitrogen doped TiO2 photocatalysts
N掺杂TiO2可见光催化降解有机物机理研究

Organic model pollutants degeneration mechanisms of photocatalytic reaction by nitrogen doped TiO2 under visible irradiation were studied.Effects of several free radical capturers on rate of photocatalytic reactions were discussed.Chemistry probe methods were used in the experiments and results demonstrated that HO· existed in the visible irradiation reaction systems.Benzene ring breaking and decolorizing of the selected organic substances were simultaneously in the reaction system,which explained that the degeneration of the organisms was completed by the non-selective oxidant attack.The substances produced by HO· attack of dimethyl sulphoxide was azo dye which had maximum absorbance at 425 nm.2,3-DHBA(dihydroxy benzyl acid) and 2,5-DHBA were the initial products of salicylic acid reaction with HO·,these substances existing in the visible reaction systems demonstrated the radical mechanisms of the reaction.After 5 h visible light photochemical catalysis degradation,TOC concentration of the methylene blue,phenol and salicylic acid reduced 62.8%,78.9% and 96.0%,respectively,these results demonstrated that nitrogen doped TiO2 can degrade organics by visible irradiation.