离子液体辅助N,S,F共掺杂纳米TiO2的制备与表征

以TiCl4、硫脲和离子液体(C6mim]+BF4]-)为原料,采用微波催化水解法合成掺杂的纳米TiO2前驱体,在NH3/N2气氛中经程序升温煅烧处理制得N,S,F共掺杂TiO2光催化剂(N—S—F—TiO2)。采用X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis/DRS)等对该光催化剂的结构和性能进行表征。结果表明,该光催化剂为锐钛矿晶型,具有较高的纯度和结晶度,掺杂在TiO2晶体中形成Ti—O—N键,Ti—O—S键,Ti—S键,而F以TiOF2形态掺杂。在可见光区400～550nm具有强吸收,且在600～800nm出现一个较强的吸收带。实验表明,使用C6mim]+BF4]-与H2O的体积比为5/95所制得的光催化剂对甲基橙降解的催化活性最高,可见光照射200min降解率达95%。多掺杂的协同效应使得N—S—F—TiO2具有对可见光的强烈吸收和较高的可见光催化活性。

Preparation and characterization of N, S, F-codoped nanosize TiO2 with ionic liquid

N, S, F-co-doped TiO2 visible-light response photocatalyst (N-S-F-TiO2) was prepared with TiCl4, thiourea and ionic liquid (C6 mim]+ BF4) via the microwave-catalytic hydrolysis precipitation process followed by calcination in an NH3/N2 atmosphere. It was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffusion reflectance spectroscopy (UV-Vis/DRS). Results showed that it was high purity anatase. The Ti-O-N, Ti-O-S and Ti-S bonds were formed in the TiO2 crystal and F used to dope TiO2 in the form of TiOF2. In the visible region 400 -550 nm, it has strong absorption, and in 600-800 nm there was a strong absorption band. N-S-F-TiO2 prepared at volume ratio of C6 mim]+ BF4]- /H2O of 5/95 exhibited the highest photocatalytic activity, and the degradation ratio of methyl orange was 95% under visible-light irradiation for 200 min. Multi-element co-doped synergistic effect was demonstrated by enhancement of the absorption in the visible region and higher visible light photocatalytic activity for N-S-F-TiO2.