钒钛催化剂制备方法对甲醇氧化制二甲氧基甲烷反应性能的影响

Influence of preparation methods of V-Ti catalysts for methanol oxidation to dimethoxymethane

分别用快速燃烧法(RC)、共沉淀法(CP)、浸渍法(IM)和机械混合法(PM)制备了钒钛催化剂,并将其应用于甲醇氧化一步法合成二甲氧基甲烷的反应中。同时采用X射线衍射(XRD)、N2吸附/脱附(BET)、NH3程序升温脱附(NH3-TPD),H2程序升温还原(H2-TPR)等多种手段对催化剂进行了表征。结果表明RC催化剂上钒的分散度最高,酸中心数最多,同时氧化还原能力较强。甲醇氧化反应结果表明,RC催化剂上甲醇转化率和DMM选择性最高,这可能与RC上较高的钒分散度,较强的氧化还原能力和较多的酸性中心数有关。

The vanadia-titania catalysts prepared by the rapid combustion method (RC),coprecipitation method (CP),impregnation method (IM) and the physical mixing method (PM) are applied to the one-step oxidation of methanol to dimethoxymethane.The catalyst structure,surface acidity and redox preperties are characterized by X-ray diffraction (XRD),Raman spectroscopy (LRS),BET surface areatest,NH3-temperature programmed desorption (NH3-TPD) and H2-temperature programmed reduction (H2-TPR) techniques.The results show that the RC catalyst employs the highest vanadia dispersion,the maximal number of acid sites and stronger reducibility.The methanol oxidation results show that the methanol conversion and DMM selectivity are the highest on the RC catalyst,which might be related to higher vanadia dispersion,more acid sites and stronger reducibility.