Guo Meilan, Gao Yun, Shao G
Institute for Renewable Energy and Environmental Technologies, University of Bolton, Bolton, BL3 5AB, UK.
Faculty of Materials Science and Engineering, Hubei University, Wuhan, 430062, China.
Phys Chem Chem Phys. 2016 Jan 28;18(4):2818-29. doi: 10.1039/c5cp05318h.
Mn-doped TiO2 powders with a wide range of nominal doping levels were fabricated using a one-step hydrothermal method followed by 400 °C annealing. Anatase powders with a uniform size distribution below 10 nm were obtained. The maximum solubility of Mn in the TiO2 lattice was around 30%, beyond which the Mn3O4 compound appeared as a secondary phase. The optical absorption edges for Mn-doped anatase TiO2 were red-shifted effectively through increasing Mn content. Alloying chemistry and associated elemental valences were elaborated through combining X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and theoretical simulation in the framework of density functional theory (DFT). The results showed that the Mn species exhibited mixed valence states of 3+ and 4+ in anatase TiO2, with the latter being the key to remarkable photocatalytic performance.
采用一步水热法并在400°C退火制备了具有广泛名义掺杂水平的锰掺杂二氧化钛粉末。获得了尺寸分布均匀且小于10nm的锐钛矿粉末。锰在二氧化钛晶格中的最大溶解度约为30%，超过该溶解度，四氧化三锰化合物会作为第二相出现。通过增加锰含量，锰掺杂锐钛矿二氧化钛的光吸收边有效地发生了红移。通过结合X射线光电子能谱（XPS）、X射线吸收光谱（XAS）以及在密度泛函理论（DFT）框架下的理论模拟，阐述了合金化化学及相关元素的价态。结果表明，锰物种在锐钛矿二氧化钛中呈现3+和4+的混合价态，其中后者是显著光催化性能的关键。
