钒含量和焙烧温度对V2O5/TiO2催化剂物理和化学性质的影响

 V₂O₅/TiO₂催化剂中活性组分状态对催化性能影响很大,影响活性组分状态主要是活性组分含量以及在不同温度下的焙烧.本文通过溶胶-凝胶法制备V₂O₅/TiO₂催化剂,运用X射线荧光光谱(XRF)、X射线衍射(XRD)、氮吸附/脱附(BET)、X射线光电子谱(XPS)、拉曼光谱(Raman Spectroscopy)和透射电镜(TEM)对所制备的催化剂进行了结构表征.XRD和TEM表明定量掺杂活性组分可以提高催化剂的热稳定性,且活性组分很均匀的分布在催化剂之中.BET、XPS和Raman光谱表征表明,催化剂结构、活性组分状态受活性组分含量和焙烧温度影响.活性组分含量和焙烧温度对催化剂的物理和化学性质有强烈影响,主要表现在催化剂的热稳定性、相组成、活性组分分散性和状态,并最终表现在用氨选择性催化还原氮氧化物反应的催化活性上.

Effect of Vanadia Loadings and Calcination Temperature on Physical and Chemical Characteristics of V2O5/TiO2 Catalyst

The catalytic activity of titania-supported vanadia catalysts was influenced by the state of the active components which were affected by the content of the active components and different calcination temperature. The catalysts were synthesized by sol-gel method and characterized by X-ray Fluorescence Spectroscopy (XRF), X-ray Diffraction (XRD), BET, X-ray Photoelectron Spectroscopy (XPS), Raman Spectra and Transmission Electron Microscopy (TEM). XRD and TEM indicated that quantitative doped active components enhanced thermal stability of the prepared samples and vanadia was well dispersed in the catalyst. BET, XPS and Raman spectroscopy revealed the structure of the catalyst and the state of active components was strongly dependent on vanadia loadings and calcination temperature. These findings were suggested that both vanadia loadings and calcination temperature affect physic and chemical characteristics, resulting in thermal stability and phase composition of the catalyst, higher dispersions and state of active components, ultimately show the catalytic activity of selective reduction reaction for removal of nitrogen oxide by ammonia.