以碳纳米管为载体,采用等体积浸渍法制备了一系列Cu Co Ce催化剂,考察了碳纳米管长度及羧基官能团对该系列催化剂催化合成气制低碳醇反应性能的影响;采用X射线衍射(XRD)、氮气吸附-脱附、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等手段对催化剂进行了结构和性能表征.实验结果表明,以含有羧基官能团的、长度为0.5~2μm的碳纳米管为载体时,催化剂的低碳醇时空收率最高,达到783.72mg·gcat-1·h-1,醇产物中C2+醇选择性达到82.71%.研究结果表明,短纳米管有利于活性金属进入碳纳米管内部,并促使活性组分分散均匀,这对CO转化率和低碳醇时空收率的提高有显著作用;碳纳米管上羧基官能团的存在促进了金属与金属、金属与载体之间的相互作用,从而使醇产物中C2+醇选择性明显提高.
A series of Cu Co Ce catalysts was prepared by co-impregnation method using different carbon nanotubes as support. In order to improve alcohol synthesis property,the effects of the length and carboxyl group of carbon nanotubes on Cu Co Ce catalysts were investigated. The catalysts were characterized by X-ray diffraction,N2adsorption-desorption,transmission electron microscopy and X-ray photoelectron spectroscopy.The results showed that the catalyst supported on carbon nanotubes of 0. 5—2 μm with 2. 0%( mass fraction)carboxyl group had highest space-time yield( 783. 72 mg · g-1cat·h-1) and the selectivity of C2+OH reached82. 71%. The study showed that the short nanotubes can promote more metal particles into the interior of carbon nanotubes and make activity components disperse uniformly,which can significantly improve the conversion of CO and the space-time yield of alcohols. Existence of carboxyl group on carbon nanotubes can enhance the interaction between active metal and support,which can remarkably increase the selectivity of C2+OH.