Mixed Alcohol Synthesis from Syngas on K–Co–Mo/C Catalyst Prepared by a Sol–Gel Method

Abstract

A kind of K–Co–Mo/C catalyst with homogenous components distribution and small particle size was prepared by sol–gel method with citric acid as complexant. Its structure and catalytic performance for mixed alcohol synthesis were investigated. By heat treating the dried gel in argon, the decomposition of citric acid resulted in the formations of amorphous carbon and low-valence MoO₂ species. The incorporation of potassium and cobalt increased significantly the alcohol synthesis activity, especially improved the C₂₊OH selectivity. The optimal atomic composition of catalyst was: 0.10 K: 0.50 Co: 1.0 Mo. Comparing with the similar catalysts reported in literatures, the sol–gel derived K–Co–Mo catalyst showed better performance, especially much higher C₂₊OH selectivity for mixed alcohol synthesis. A 150 h reaction test indicated that the catalyst had good stability during the entire experimental period. It suggested that the homogenous components distribution and small particle size enhanced the synergistic effect of promoters and created more active species, leading to a high catalytic performance. The formation of MoO₂ species was also favorable to improve the catalytic activity because the low-valence Mo⁴⁺ was known to be more active in CO hydrogenation.