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

Abstract

Several unsupported and supported molybdenum-based catalysts were prepared by precipitation and impregnation, and characterized by N₂ adsorption, XRD, H₂-TPR, and XPS. The catalytic activity for alcohol synthesis was evaluated using a fixed-bed pressurized flow reaction system under the following conditions: 250-350 °C, 5.0 MPa, GHSV of 5000 h⁻¹, and H₂/CO ratio of 1.0. Addition of Co to the unsupported MoS₂-bulk catalyst enhanced the selectivity for C₂₊ alcohols and total alcohols, and reduced the selectivity for hydrocarbons. Addition of K to Co₀₄MoS improved the selectivity for total alcohols and suppressed the formation of hydrocarbons, increased the selectivity for methanol and CO₂, and decreased carbon-chain growth. The alumina-supported catalyst was the most favorable for Fischer-Tropsch synthesis but was unfavorable for C₂₊ alcohol synthesis. The silica-supported catalyst was more favorable for C₂₊ alcohol synthesis than the unsupported catalyst.