Selective conversion of CO2 to methanol by catalytic hydrogenation over promoted copper catalyst

As a chemical fixation and/or recycling technology of emitted CO2, a selective and effective conversion of CO2 to methanol by catalytic hydrogenation over promoted CuZnO catalyst has been studied. To obtain a high methanol selectivity, both a high pressure and a low temperature are required. The influence of contact time on the methanol selectivity was also demonstrated. It shows that methanol is directly produced from CO2 at low conversion as suggested by in situ FT-IR study, however, at high conversion, near the equilibrium, produced CO could also contribute to the methanol formation. The reduction temperature of catalyst influenced not only the catalyst structure but also the CO2 conversion and the methanol selectivity. Methanol yield was proportional to Cu metallic surface area of catalyst, and the CO2 hydrogenation to methanol over our catalysts was not a remarkable structure sensitive reaction. Finally, methanol was produced with 79 % selectivity, 20 % yield and 25 % CO2 conversion over CuOZnOAl2O3Cr2O3 catalyst at the condition of 7 MPa, 250 °C, GHSV=1800 h−1 and H2/CO2=3/1.