Hydrogenation of CO2 on group VIII metals IV. Specific activities and selectivities of silica-supported Co, Fe, and Ru

Specific intrinsic rates and product distributions for CO2 hydrogenation on Co/SiO2, Fe/SiO2, and Ru/SiO2 were determined at 450–650 K, 140–1030 kPa, and a range of space velocities. Specific activities in the form of turnover frequencies for CO2 hydrogenation decrease in the order Co/SiO2, Ru/SiO2, Ni/SiO2, Fe/SiO2. The order of decreasing selectivity for methane is Ru/SiO2, Co/SiO2, Ni/SiO2, Fe/SiO2. High levels of CO are produced in CO2 hydrogenation on Fe/SiO2, Co/SiO2, and Ni/SiO2 while significant fractions of C2+ hydrocarbons (about 1 order of magnitude lower than typical methane fractions) are produced on Fe/SiO2 and Co/SiO2 catalysts.