Hydrogenation of carbon dioxide and carbon monoxide over supported platinum catalysts

Abstract

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.