Abstract
Synthesis gas conversion over a 1 wt% Rh-5 wt% K-10 wt% MoP on SiO2 catalyst was investigated at different temperatures, synthesis gas H-2/CO ratios and space velocities. Compared to a 5 wt% K-10 wt% MoP on SiO2 catalyst, addition of Rh increased the stability of the catalyst and the selectivity to hydrocarbons. The highest C2+ oxygenate selectivity of 44 C atom% was achieved at 598 K and H-2:CO = 1. Power law kinetics were used to describe the space-time yield (STY) of the major products. The apparent activation energies for ethanol (77.7 kJ/mol) and acetaldehyde (81.9 kJ/mol) formation suggested that both originated from the same surface intermediate whereas, a higher activation barrier was identified for methanol (114.5 kJ/mol). (C) 2011 Elsevier B.V. All rights reserved.