Al含量对完全液相法制备Cu-Zn-Al催化剂合成甲醇的影响

Effect of Al Content on Synthesis of Methanol over Cu-Zn-Al Catalyst Prepared by Complete Liquid-phase Technology

采用完全液相催化剂制备工艺,以异丙醇铝为铝源,在固定n(Cu)∶n(Zn)比例下,考察了Al含量对Cu-Zn-Al浆状催化剂合成甲醇的影响,通过X射线粉末衍射(XRD)、程序升温还原(TPR)、氮气吸附(BET)、X射线光电子能谱(XPS)等对催化剂进行了表征。研究表明,Al含量对催化剂的催化性能有显著的影响,较多或较少的Al含量都不利于甲醇合成;当n(Cu):n(Zn):n(Al)=2∶1∶0.8时催化剂具有最高的甲醇选择性。增加Al含量有利于提高Cu物种的分散性;当Al含量增加到一定量后,催化剂的比表面积会迅速增加。

The Cu-Zn-Al slurry catalysts were prepared by complete liquid-phase technology with aluminium isopropoxide as aluminum source. The effect of Al content in catalysts with the fixed ratio of n（Cu）/n（Zn） on synthesis of methanol was investigated. The catalysts were characterized by X-ray diffraction （XRD）, H2 temperature-programmed reduction （H2-TPR）, N2 adsorption （BET）, X-ray photoelectron spectroscopy （XPS）. The results show that Al content had significant influence on the catalyst performance. An optimum Al content existed for the synthesis of methanol,that is, the catalyst prepared with n（Cu）： n（Zn） ：n（A1）=2 ：1 ： 0.8 had the highest selectivity of methanol. The catalyst had better Cu dispersion as the increase of Al content, the BET surface area increased rapidly when A1 content increased to a certain amount.