Enhancement of stability and activity of Cu/ZnO/Al2O3 catalysts by colloidal silica and metal oxides additives for methanol synthesis from a CO2-rich feed

A series of Cu/ZnO-based catalysts were prepared through co-precipitation and alternative pH precipitation methods by adding small amount of colloidal silica (0.6 wt.%) and Mn, Ga and Zr oxides for methanol synthesis from a CO2-rich feed. The prepared catalysts were characterized by a variety of techniques, including X-ray diffraction, N2O chemisorption, temperature programmed reduction, BET and TEM. Catalytic tests were carried out in a fixed bed reactor at 4.5 MPa and 513 K with a mixture of CO/CO2/H2 = 1/1.38/16.5 and GHSV of 15,000 h–1. An accelerated thermally induced deactivation test was performed in the middle of the catalytic performances. During accelerated thermal test and after rising the temperature, an upward trend was observed for space time yield (STY) over the catalysts. The experimental results indicated that a small amount of SiO2 and the oxide additives could significantly improve the catalyst activity and stability.