Sol–gel Preparation of K–Co–Mo Catalyst and its Application in Mixed Alcohol Synthesis from CO Hydrogenation

Abstract

A kind of K-Co-Mo catalyst with large surface area, small particle size and homogenous components distribution was prepared by sol-gel method using citric acid as complexant, and characterized by XRD, BET, HR-TEM, EXAFS and TPD techniques. The activity for mixed alcohol synthesis from syngas on the catalysts was investigated. During the preparation, a gelation process was adopted to prevent the components from precipitating during the solvent extraction and keep the homogeneity and small particle size of final products. Heat-treated the dried gel in argon, the decomposition of critic acid partly reduced the sample and decreases the particle sizes remarkably. The synthesized K-Co-Mo catalyst exhibited excellent performance for mixed alcohol synthesis from CO hydrogenation, which may be due to its large surface area and small particle size creating more active sites. Beside it, the homogeneity of various components was also helpful to enhance the synergistic effect of Co promoters. The high selectivity to the C 2+ OH was due to the large amount of SH species adsorbed on the catalyst surface.

Effects of Adding Cobalt and Potassium to MoS₂-based Catalysts on Mixed Alcohol Synthesis

“…Our previous study investigated the effects of acidity on the supports or catalysts in mixed alcohol synthesis 6) . In other reports, the selectivities for C2 alcohols with unsupported and activated carbon-supported K _ Co _ MoS2 were 71-72 % 20), 21) and 84-90 % (CO2 excluded) 22) 25) , respectively. CO conversion with either unsupported or supported catalyst was 13-15 %.…”

Mixed MgAl Oxide Supported Potassium Promoted Molybdenum Sulfide as a Selective Catalyst for Higher Alcohol Synthesis from Syngas

“…These catalysts include modified Fischer-Tropsch or methanol synthesis catalysts, which are typically adapted for alcohol synthesis by adding promoters such as alkali or other transition metals. Another class of catalysts developed in the late 1980s for these reactions is based on alkali promoted molybdenum sulfide [6][7][8][9] which is commonly combined with cobalt [10][11][12][13]. While molybdenum sulfide based catalysts facilitate reactions that are largely selective for alcohols, their catalytic activity relative to noble metal catalysts, such as those based on Rh, is lower [14][15][16][17][18][19].…”

X‐ray Absorption Spectroscopy of an Fe‐Promoted Rh/TiO2 Catalyst for Synthesis of Ethanol from Synthesis Gas

“…Higher alcohol synthesis (HAS) catalysts have received a great deal of attention and recent literature is abundant with catalysts and processes for HAS. [1][2][3][4][5][6][7][8][9][10][11][12] The literature focuses on differently-supported and promoted Rh and Mo catalysts as well as modified Cu-based methanol synthesis catalysts and modified Fischer-Tropsch catalysts. Two excellent reviews on heterogeneous catalysts for the synthesis of higher alcohols from syngas have recently appeared.…”