Liu Shouxin, Chen Xiaoyun
College of Material Science and Engineering, Northeast Forestry University, Harbin 150040, Heilongjiang, China.
J Hazard Mater. 2008 Mar 21;152(1):48-55. doi: 10.1016/j.jhazmat.2007.06.062. Epub 2007 Jun 22.
S-doped TiO2 photocatalyst with high visible light activity was prepared by acid catalyzed hydrolysis method using thiourea (TU) as sulfur source. The catalyst was characterized by DRS, XPS, XRD, FTIR, SEM and N2 adsorption. It was found that cation S6+ was homogeneously incorporated into the bulk phase of TiO2 and substitutes for some of the lattice titanium (Ti4+). Doped S can form a new band above the valence band and narrow the band-gap of the photocatalyst, giving rise to a second absorption edge in the visible light region. The activity of the catalyst was examined by photodegradation of phenol in aqueous solution under both artificial visible light and solar light irradiation. The activity of catalyst was found to be dependent on the doping amount of S and the maximum activity was observed when the catalyst was obtained by calcinated at 600 degrees C with the mass ratio of TU/TiO2=1. Too much of new-generated band-gap structures due to higher S-doping could act as recombination centers for electron-hole pairs. Catalyst with optimum S-doping exhibited the highest activity under both artificial light and solar irradiation for phenol degradation. In addition, doped S also beneficial for the better dispersion, large S(BET) and phase transformation retardation of TiO2.
采用硫脲（TU）作为硫源，通过酸催化水解法制备了具有高可见光活性的S掺杂TiO₂光催化剂。通过漫反射光谱（DRS）、X射线光电子能谱（XPS）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和N₂吸附对催化剂进行了表征。结果发现，阳离子S⁶⁺均匀地掺入TiO₂的体相中，并取代了部分晶格钛（Ti⁴⁺）。掺杂的S能在价带上方形成一个新的能带，使光催化剂的带隙变窄，从而在可见光区域产生第二个吸收边缘。通过在人工可见光和太阳光照射下对水溶液中苯酚的光降解来考察催化剂的活性。发现催化剂的活性取决于S的掺杂量，当以TU/TiO₂质量比为1在600℃煅烧得到催化剂时，观察到最大活性。由于较高的S掺杂而产生的过多新的带隙结构可能成为电子-空穴对的复合中心。具有最佳S掺杂量的催化剂在人工光和太阳光照射下对苯酚降解均表现出最高活性。此外，掺杂的S还有助于TiO₂更好地分散、具有较大的比表面积（BET）以及延缓相变。
