氮掺杂型纳米TiO_2在可见光及太阳光下的光催化性能研究

Studies on the photocatalytic activity of nitrogen-doped TiO_2 under visible light and sunlight irradiation

采用钛酸四丁酯为原料。以氨水水解-沉淀法制备出了氮掺杂型纳米TiO2催化剂（N／TiO2），以XRD、XPS、UV-Vis等手段对其进行表征；并通过对偶氮染料橙黄G的降解反应，研究了N／TiO2在可见光及太阳光下的光催化性能，探讨了pH值、外加H2O2氧化剂对光催化降解率的影响，并与P25型纳米TiO2进行了对比．结果表明，在可见光下。N／TiO2对橙黄G具有较高的催化活性，反应150min后降解率可达96．29％，显著高于P25型TiO2（42．55％）；在太阳光下。N／TiO2对橙黄G的光催化降解速率较快，反应60min降解率与P25型TiO2基本相同，分别为99．37％、99．94％；较低的pH值环境并适量添加H2O2可显著提高N／TiO2催化效率。在可见光及太阳光下的最佳pH值均为2—3，最佳H2O2加入量分别为0．5mL·L^-1、1．5mL·L^-1．

Nanosized nitrogen-doped titania （N/TiO2 ）photocatalyst was prepared by calcination of the hydrolysis product of tetrabutyl titanate with ammonia as precipitator. The catalyst was characteristieed by XRD, XPS and UV-Vis absorption spectra. The photocatalytic activity of N/TiO2 under visible light and sunlight was studied by degradation of a model azo-dye Orange G. The effects of pH and addition of hydrogen peroxide On the degradation process were also investigated. The photacatalytic activity of N/TiO2 compared with P25-TiO2 was studied in the same condition. The results showed that N/TiO2 exhibited stronger photocatalytie activity than that of P25 under visible light irradiation, and the degradation rate reached 96.29% and 42.55% in 150min, respectively. On the other hand, the photocatalytic reaction was more rapid under sunlight＋ and the degradation rate with N/TiO2and P25 reached 99.37% and 99.94% in 60min, respectively. In addition, the degradation was strongly enhanced with addition of H2 02 appropriately in acidic media. The optimal pH was 2 -3 under different light sources. The optimal addition of H2O2 was 0.5mL·L^-1 and 1.5 mL·L^-1 under visible light and sunlight.