介孔碳有序度对其负载的CuCoCe催化剂催化合成气制低碳醇性能的影响

Effect of Structural Ordering on the Performance of Mesoporous Carbon Supported CuCoCe Catalyst in the Synthesis of Higher Alcohols from Syngas

采用软模板法,通过调变碳源甲醛和间苯二酚的摩尔比,制备了3种不同有序度的介孔碳;并以其为载体,采用超声辅助等体积浸渍法制备了Cu Co Ce/介孔碳催化剂;考察了孔道结构有序度对其催化合成气制低碳醇性能的影响.采用X射线衍射(XRD)分析、N2吸附-脱附实验、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等对催化剂进行了表征.实验结果表明,随着介孔碳有序度的提高,催化活性呈增加趋势.以高度有序的介孔碳作为载体时,低碳醇的时空收率和选择性分别达到849.96 mg·g-1cat·h-1和50.48%,醇产物中C2+OH比例达到90.31%.研究表明,孔道结构影响了活性金属在载体上的分布及存在状态.规整有序的二维六方直通孔结构有利于活性组分Cu Co的均匀分散并使其紧密结合,促进了二者之间的电子转移,进而有效抑制了碳链的持续增长,使催化剂的活性明显提高,并缩窄了醇产物的分布.

Three kinds of mesoporous carbons were synthesised via soft-templating methods by adjusting the molar ratio of formaldehyde and resorcinol in the carbon source. The Cu Co Ce catalysts supported on different mesoporous carbons were prepared by co-impregnation method. The effect of structural mesopore ordering to catalytic properties for higher alcohol synthesis from syngas was studied in this passage and the catalysts were characterized by X-ray diffraction（ XRD）,N2 adsorption-desorption（ BET）,transmission electron microscopy（ TEM） and X-ray photoelectron spectroscopy（ XPS）,etc. The results show that the catalytic property has been constantly improved with the improvement of mesopore ordering. The catalyst supported on the highly ordered mesoporous carbon has the highest space-time yield（ 869. 14 mg · g-1 cat· h-1） and selectivity（ 50. 48%） of higher alcohols,where the mole fraction of C2＋OH reached 90. 31% in the alcohol products.This study show that the pore structure affects the distribution and presence of active metals on the support. Highly ordered 2 D hexagonal straight pore channels are conducive to the uniform dispersion of the active component Cu Co and its close association,which promot the electron transfer between the two,thereby effectively inhibiting the continuous growth of the carbon chain,resulting in a significant increase in the activity of the catalyst and narrowing the distribution of the alcohol product.