Methanol Synthesis Using CO2 Rich Syngas Over Cu/Zn-Based Cataysts

Methanol is readily available as a hydrogen source and can be convert into hydrogen-rich gas at morderate temperature. However, Conversion of CO₂ rich syngas to methanol is difficult because of thermal dymanic limitation. In this study, methanol synthesis from CO₂ rich syngas was studied over a seriess of Cu/Zn-based catalysts such as Cu/ZnO, Cu/ZnO/Al₂O₃, Cu/ZnO/ZrO₂/Al₂O₃ in a continuous flow fixed bed reactor.

Cu/Zn-based catalysts were derived from hydrotalcite-like precursors prepared by a co-precipitation of metal nitrates in a aqueous solution. The catalysts are characterized by CO chemisorption, TPR, XRD and BET surface area measurements.

By ZrO₂ added to the Cu/Zn-based catalyst enhances copper dispersion on the catalyst surface. Also, ZrO₂ added to the Cu/Zn-based catalyst exhibits lower reduction temperature than that of Cu/Zn-based catalyst without ZrO₂.

Among the catalysts tested, Cu/ZnO/ZrO₂/Al₂O₃ exhibits the highest CO2 conversion and methanol yield. This results show that ZrO₂ added to Cu/Zn-based catalysts plays an important role in enhancing Cu dispersion and in forming small size Cu particles on the catalyst surface. So, small Cu particles on the catalyst surface improve activity of methanol sythesis reaction.