Al含量对完全液相法制备Cu-Zn-Al催化剂合成甲醇的影响

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。

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

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(Al)=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 Al content increased to a certain amount.