Microwave‐Assisted Hydrothermal Synthesis of CuO–ZnO–ZrO 2 as Catalyst for Direct Synthesis of Methanol by Carbon Dioxide Hydrogenation

A series of CuO–ZnO–ZrO 2 catalysts was prepared by a facile microwave‐assisted hydrothermal synthesis method and used for the direct synthesis of methanol by CO 2 hydrogenation in a fixed‐bed reactor at 240 °C, 3.0 MPa, CO 2 /H 2 =1:3 ( v / v ), and space velocity of 2400 mL g cat −1  h −1 . The effects of the hydrothermal synthesis temperature (80–150 °C) on the physicochemical properties and catalytic activity of the CuO–ZnO–ZrO 2 catalysts were investigated by using several techniques, including XRD, N 2 adsorption, reactive N 2 O adsorption, SEM with energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, temperature‐programmed reduction by H 2 , and the temperature‐programmed desorption of adsorbed CO 2 and H 2 . The catalyst prepared at 120 °C possessed a high surface area, a high dispersion of Cu species, a high adsorption capacity for CO 2 and H 2 , and thus exhibited a high CO 2 conversion and methanol selectivity. The surface area of metallic Cu ( S Cu ) is the critical factor in determining the activity of the CuO–ZnO–ZrO 2 catalyst.