Cu/Fe组成对CuFe基低碳醇催化剂的反应性能的影响

采用共沉淀法制备了一系列不同Cu/Fe摩尔比的CuFe基低碳醇催化剂,采用XRD、XPS、BET、H2-TPR等手段对其进行了表征,并对其CO加氢合成低碳醇性能进行了考察。结果表明,随着Cu/Fe摩尔比的增大,总醇和C2+OH选择性明显升高,醇的链增长因子则由0.29升至0.39,且其醇产物分布符合Anderson-Schulz-Flory(A-S-F)分布。随着Cu/Fe摩尔比的增加,表面金属元素更多的以CuFe2O4、CuMn2O4等复合金属氧化物的形式存在,Cu-Fe协同作用增强,这有利于提高催化剂的醇选择性和C2+OH选择性;同时,随着Cu/Fe摩尔比的增大,孔径与孔体积的明显增大,这也有利于提高C2+OH选择性。

Effect of Cu/Fe ratios on catalytic performances of co-precipitated Cu-Fe based catalysts for higher alcohols synthesis

A series of Cu-Fe based catalysts with different Cu/Fe ratios were prepared by co-precipitation.Structure properties of the catalysts were characterized by XRD,XPS and BET and catalytic performances of the catalysts for C1~5 alcohols synthesis from syngas were investigated in a fixed bed flow reactor.The results showed that,with the increase of Cu/Fe ratio in catalysts,the selec-tivities of total alcohols and C2+OH significantly enhanced,and chain probability growth factor for alcohols rose from 0.29 to 0.39,while the alcohol products obeyed A-S-F distribution.With the increase of Cu/Fe ratio,the surface interaction between copper and iron or other metal elements became stronger and consequently formed composite oxide phases(such as CuFe2O4,CuMn2O4),which enhanced the synergistic effects between Cu and Fe,and improved the selectivities of alcohols and C2+OH.With the increase of Cu/ Fe ratio,the pore size and pore volume of Cu-Fe based catalysts became also much larger which resulted in improving formation of long-chain alcohols.