CuO-Fe2O3-CeO2/HZSM-5 bifunctional catalyst hydrogenated CO2 for enhanced dimethyl ether synthesis

• CuO-Fe2O3 catalyst modified with different amounts of CeO2 were prepared.
• Addition of CeO2 led to the formation of a stable Cu-O-Ce solid solution.
• CeO2 can modify the amount of acid sites and acid type of CuO-Fe2O3 catalyst.
• Cu-Fe-Ce/HZSM-5 catalyst with 3.0 wt% CeO2 showed the optimal catalytic activity.

A series of CuO-Fe2O3-CeO2 catalysts with various CeO2 doping were prepared via the homogeneous precipitation method, characterized and mechanically mixed with HZSM-5. Their feasibility and performance for the synthesis of dimethyl ether (DME) via CO2 hydrogenation in a one-step process were evaluated. The formed stable solid solution after the CuO-Fe2O3 catalyst modified with CeO2 promoted the CuO dispersion, reduced the CuO crystallite size, decreased the reduction temperature of highly dispersed CuO, modified the specific surface area of the CuO-Fe2O3-CeO2 catalyst, and improved the catalytic activity of the CuO-Fe2O3-CeO2 catalyst. The addition of CeO2 to CuO-Fe2O3 catalyst increased the amount of Lewis acid sites and Brønsted acid sites, and enhanced the acid intensity of the weak acid sites, which in turn promoted the catalytic performance of CO2 hydrogenation to DME. The optimal introduced amount of Ce in the catalyst was determined to be 3.0 wt%. The CO2 conversion and DME selectivity were 20.9%, and 63.1%, respectively, when the CO2 hydrogenation to DME was carried out at 260 °C, and 3.0 MPa with a gaseous hourly space velocity of 1500 mL gcat−1 h−1.

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