氮掺杂暴露(001)面二氧化钛的制备及其可见光催化性能研究

Hydrothermal synthesis of N-doped TiO_2 nanosheets and their visible light photoactivity

以尿素为氮源、HF为调控剂,采用水热法制备了以(001)活性面为主的氮掺杂型TiO2催化剂.SEM、TEM、XRD、Raman及UV-Vis测试结果表明,TiO2及N-TiO2产品均为暴露(001)面的纳米片状锐钛矿结构,TiO2在高温900℃煅烧仍能保持锐钛矿结构.F-不仅对(001)面的暴露起到很好的调控作用,而且抑制了TiO2在高温下向金红石相的转化.氮的掺杂窄化了TiO2的禁带宽度,使其边带红移,在可见光区域有很强的吸收峰.并且,随着氮掺杂量的增多,N-TiO2在可见光的吸收峰增强.以可见光降解染料罗丹明B溶液作为探针反应,研究了不同N/Ti配比的N-TiO2的可见光催化活性,氮掺杂TiO2的可见光催化活性比照纯TiO2有明显的改善.

N-doped titanium dioxide nanosheets were successfully prepared using urea as the nitrogen source by a facile one-step hydrothermal method with the assistance of hydrofluoric acid. Using the photodecomposition of rhodamine B as a probe,we study the photocatalytic activity of different N/Ti mass ratio under visible light irradiation. The results show that the obtained undoped TiO2 and N- doped TiO2nanosheets had the anatase phase and exhibited good thermal stability. It is believed that fluorine plays the roles on both stabilization on the （001） facets as a morphology controlling agent and enhancement in the crystallization of anatase phase of TiO2. The bands of the N-doped TiO2 ma- terials have a quite redshift,a stronger absorption in the visible light region. In the photodegradation of rhodamine B in the visible light irradiation, photocatalytic activities of nitrogen-doped titania are greatly improved compared with the undoped TiO2.