CO hydrogenation on group VI metal–ceria catalysts

• Ceria supports showed the best performance among ceria, SiO2, and Al2O3 supports.
• For group VI metal-based catalysts, Mo-based catalyst most favored C2 + alcohol yield.
• The sulfidation favored the formation of C2 + alcohols for the activation methods.
• The CoMoS phase played an important role in C2 + alcohol synthesis.

Ceria-supported chromium, molybdenum, and tungsten catalysts were prepared by impregnation. The prepared catalysts were characterized using N2 adsorption, X-ray diffraction (XRD), the temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) measurements. The catalytic activity in CO hydrogenation was evaluated using a fixed-bed pressurized flow reaction system under the following conditions: 260–300 °C, 5.0 MPa, GHSV of 5000 h− 1, and a H2/CO ratio of 1.0–2.0. The effects of ceria support, group VI metals, and catalyst activation methods on C2 + alcohol synthesis were investigated. The use of ceria supports resulted in a decrease in the selectivity for CO2, and in increases in the selectivity for C2 + alcohols and CO conversion. The selectivity for alcohols on the Mo-based catalysts was higher than those on the corresponding Cr or W-based catalysts. A comparison of the methods of activation for the K005Co0620MoCe catalyst demonstrated that sulfidation produced the highest CO conversion and selectivity for C2 + alcohols, as well as the lowest, hydrocarbon selectivity. XPS and H2-TPR measurements show that the mixed metal sulfide phases, e.g., the Co–Mo–S phase, and the thiol group on the catalysts enhanced the formation of C2 + alcohols.

Effects of group VI metals on CO conversion and selectivities in the synthesis of C2 + alcohols for presulfided + reduced K(C)005Co06MCe (M = 8.6 Cr, 15 Mo, 22 W) at 280 °C, H2/CO = 2.0, 5.0 MPa, and 5000 h− 1. (HCs: hydrocarbons, Conv.: CO conversion).Figure optionsDownload as PowerPoint slide