助催化剂Mg、Sr对Co/AC催化剂CO加氢制备高碳混合醇反应性能的影响

采用共浸渍法制备了不同Mg和Sr含量的15%Co-x%M/AC催化剂,考察其CO加氢制高碳混合醇的性能。结果表明,添加适量Mg,使催化剂的CO转化率由39.8%提高至47.4%,甲烷选择性由26.2%降至16.9%,同时醇中高碳混合醇由42.6%提高至53.5%;添加Sr明显抑制高碳混合醇的生成。通过CO化学吸附、XRD和TPR等表征发现,少量Mg能提高Co分散度,促进Co2C生成,使催化剂CO转化率增加,高碳混合醇选择性增加,甲烷选择性减少。

Effects of Mg and Sr promoters on the performance of Co/AC catalysts for CO hydrogenation to mixed higher alcohols

15%Co-x%M/AC catalysts with different loadings of Mg and Sr were prepared by the co-impregnation method,and their catalytic performance was investigated by means of CO hydrogenation.The results indicated that with the addition of appropriate amount of Mg,CO conversion was increased from 39.8% to 47.4%,the selectivity to CH₄ was decreased from 26.2% to 16.9%,and the proportion of higher alcohols was improved from 42.6% to 53.5% in the total alcohols,but the formation of higher alcohols was restrained obviously by adding Sr.The results of CO chemisorption,XRD,and H₂-TPR characterization showed that a little amount of Mg enhanced Co dispersion,and promoted the formation of Co₂C species,which resulted in the increase of CO conversion,the selectivity to higher alcohols,and the decline of selectivity to CH₄.