The effect of adding Ag to CuO-ZrO2 catalysts for the hydrogenation of CO2 to methanol was investigated using CuO-ZrO2, Ag/CuO-ZrO2, and Ag/ZrO2. The addition of Ag to CuO-ZrO2 catalysts decreased the specific surface area and also broke its mesostructure. Thus, Ag played a significant role as a sintering aid in the preparation of Ag/CuO-ZrO2 catalysts. We note that the as-prepared Ag/CuO-ZrO2 catalysts contained Ag+ and Zr q + (q <4) sites and that the Zr q + content increased with increasing Ag+ content. Furthermore, the presence of CuO in the Ag/CuO-ZrO2 catalyst appeared to stabilize Ag+ and Zr q + species under air. Based on H2 chemisorption and powder X-ray diffraction patterns, formation of a Ag-Cu alloy was observed on completely reduced and spent Ag/CuO-ZrO2 catalysts. Completely reduced Ag/CuO-ZrO2 catalysts exhibited a higher methanol production rate (7.5mLhâˆ’1 gcat âˆ’1) compared to completely reduced CuO-ZrO2 (6.9mLhâˆ’1 gcat âˆ’1) and Ag/ZrO2 catalysts (2.2mLhâˆ’1 gcat âˆ’1) under the following reaction conditions: CO2/H2/N2 =1/3/1, catalyst loading=500mg, W/Ftotal =1000mgcat smLâˆ’1, reaction temperature=230Â°C, pressure=10bar.