硼掺杂TiO2/SO42-的合成及其可见光催化性能

Synthesis of Boron-Doped TiO2/SO42- Photocatalysts and Their Visible-light Photocatalytic Performances

摘要:

采用固相热分解法制备了一系列B-TiO2/SO42-光催化剂，通过XRD、FT-IR、UV-Vis DRS和XPS等测试手段对其晶相结构、紫外漫反射谱和表面化学形态进行了表征，并考察了紫外光和可见光照射下硼掺杂用量分别对降解污染物亚甲基蓝的影响。结果表明，硼原子以填隙方式进入氧化钛晶格间隙，且在氧化钛表面形成的Ti-O-B键对表面羟基和表面硫酸化的形成都有显著的影响。UV-Vis DRS分析显示硼掺杂可以增强氧化钛的紫外光吸收，且硼钛摩尔比的增加TiO2的可见光吸收能力也随之增强。与P25相比，n(B):n(Ti)为0.25:1的氧化钛显示出了更好的紫外光和可见光降解活性，其光催化活性的提高归因于是硼掺杂氧化钛的能隙减小，表面SO42-基团对光生电子/空穴对有效分离以及表面活性羟基的协同作用。

Abstract:

A series of boron-doped TiO2/SO42- photocatalysts were successfully prepared by the solid-state thermolysis method. Several technologies including X-ray powder diffraction ( XRD), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (UV-vis DRS) and X-ray photoelectron spectroscopy ( XPS) were employed to investigate the phase structures，diffuse reflectance spectroscope (DRS) and surface chemical states. The photocatalytic properties of B-doped TiO2 were evaluated by degrading methylene blue (MB) under UV irradiation and visible-light irradiation. Results showed that B species have been doped into the crystal lattice of TiO2 with B doped in the form of substitutional and interstitial B, and can affect the surface chemical forms and structures of surface hydroxyl groups and SO42- groups. The experimental results of UV-vis DRS further indicate that the as-prepared photocatalysts with different B contents exhibited the stronger absorption in the visible light region and UV region. Compared to P25, B-doped TiO2 samples showed better activities for degradation of methylene blue (MB) under UV irradiation and visible light irradiation, and exhibited the highest photocatalytic activity when the molar doping ratio of B was 0.25. The superior performance of this sample is ascribed to the synergy and interplay among the decrease of the optical energy gap, efficient charge separation and surface hydroxyl groups.