Hydrogenation of carbon dioxide and carbon monoxide over supported platinum catalysts

The production of methanol from reactions between CO2+ H2 and CO + H2 has been studied over platinum catalysts supported on Nb2O5, ZrO2, MgO, SiO2 and TiO2. Zirconia- and niobia-supported Pt catalysts showed the highest activity for reactions of both CO2 and CO. The magnesia-supported Pt catalyst was less active compared with Pt/ZrO2 and Pt/Nb2O5, but exhibited the highest selectivity towards MeOH formation. The activation energy of the CO2+ H2 reaction was always lower than that of the CO reaction. Thus, the reaction of CO2+ H2 occurs easily at lower temperature compared with the CO + H2 reaction, but the rate of CO hydrogenation exceeds that of CO2 hydrogenation at higher temperatures. The selectivity towards methanol was higher for CO2 hydrogenation than that for the CO + H2 reaction over all the catalysts used.