| Abstract
| - Nitrogen-doped TiO2 nanocatalysts with a homogeneous anatase structure were successfully synthesized througha microemulsion−hydrothermal method by using some organic compounds such as triethylamine, urea, thiourea,and hydrazine hydrate. Analysis by Raman and X-ray photoemission spectroscopy indicated that nitrogenwas doped effectively and most nitrogen dopants might be present in the chemical environment of Ti−O−Nand O−Ti−N. A shift of the absorption edge to a lower energy and a stronger absorption in the visible lightregion were observed. The results of photodegradation or the organic pollutant rhodamine B in the visiblelight irradiation (λ > 420 nm) suggested that the TiO2 photocatalysts after nitrogen doping were greatlyimproved compared with the undoped TiO2 photocatalysts and Degussa P-25; especially the nitrogen-dopedTiO2 using triathylamine as the nitrogen source showed the highest photocatalytic activity, which also showeda higher efficiency for photodecomposition of 2,4-dichlorophenol. The nitrogen doping concentration had anoptimal value, and accordingly, the photocatalyst showed the highest photocatalytic activity. This suggestedthat nitrogen doping has important effects on the improvement of photocatalytic activity: on one hand, nitrogendoping could narrow the band gap of titania to extend the adsorption of catalyst to the visible light region;on the other hand, nitrogen doping could inhibit the recombination of the photoinduced electron and thereafterincrease the efficiency of the photocurrent carrier.
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