Low-temperature methanol synthesis catalyzed over Cu/γ-Al2O3–TiO2 for CO2 hydrogenation

Abstract

A titanium-modified γ-alumina-supported CuO catalyst has been prepared and used for methanol synthesis from CO₂ hydrogenation. XRD and TPR were used to characterize the phase, reduction property and particle size of the reduced catalyst. The addition of Ti to the CuO/γ-Al₂O₃ catalyst made the copper in the catalyst exist in much smaller crystallites and exhibit an amorphous-like structure. The adding of Ti made the reduction peak shift toward lower temperature in comparison with the CuO/γ-Al₂O₃ catalyst. The effect of the addition of Ti and the reaction conditions on the activity and selectivity to methanol from CO₂ hydrogenation were investigated. The activity was found to increase with increasing surface area of metallic copper, but it is not a linear relationship. This indicated that the catalytic activity of the catalysts depends on both the metallic copper area and the synergy between the copper and titanium dioxide. The effect of contact time on the relative selectivity (κ=SCH₃0H /S_CO) and selectivity of methanol were also investigated. The results indicated that methanol was formed directly from the hydrogenation of CO₂.