V_2O_5-TiO_2复合半导体光催化材料结构及光响应性能研究

Structures and Photo Absorption Properties of Sol-gel-derived Coupled Semiconductor V_2O_5-TiO_2

采用溶胶凝胶法制备了V2O5-TiO2复合半导体材料,通过Raman、XRD及UV-VisDRS等实验方法研究了V2O5与TiO2复合对材料表面组成、晶体结构以及光响应性能的影响。结果表明:钒加入后优先与TiO2作用形成较为稳定的金红石型TiVO4晶相,其中V4+是促进TiO2发生相变的关键;随着钒加入量的增加,V2O5由表面高分散状态逐渐聚集形成晶相,并释放部分Ti4+使之形成锐钛矿型TiO2晶相,使得体相中金红石型TiO2的含量有所下降;复合后形成的TiVO4晶相显著提高了材料对可见光的吸收率,并使其吸光域红移至460nm左右。

Coupled semiconductors V2O5-TiO2 were prepared by sol-gel method. The coupling effects of V2O5 and TiO2 on the surface composition, crystal structure and photo absorption properties of materials were investigated by the techniques of Raman spectroscopy, X-ray diffraction （XRD） and Ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis DRS）. Results show that Rutile TiVO4 is preferentially formed as the main crystal structure of coupled semiconductors. V^4＋ is the key to promote the phase transition of TiO2. With its content increasing, more V^5＋ ions gather on the surface to form V2O5 crystallites. Simultaneously, parts of Ti^4＋ are released to form Anatase TiO2. As a result, the content of Rutile TiO2 is decreased. The visible light absorption properties of coupled semiconductors are obviously enhanced for the formation of crystal TiVO4, while the absorption limits bathochromic shift to 460 nm.