Gas-phase hydrogenation of maleic anhydride to γ-butyrolactone over CeO₂-promoted Cu-ZnO catalysts

A series of CeO₂ promoted Cu-ZnO catalysts with different CeO₂ content were prepared by co-precipitation method and characterized by X-ray diffraction, N₂ adsorption-desorption (BET), hydrogen temperature-programmed reduction, N₂O chemisorption, and H₂ chemisorption. Hydrogenation of maleic anhydride to γ-butyrolactone was conducted over these catalysts in a fixed-bed continuous-flow reactor. Addition of CeO₂ not only influenced the catalyst structure significantly by decreasing the CuO particle size, increasing the BET surface area, and Cu⁰ active area, but also had a significant enhancements in both reducibility and H₂ uptakes of the catalysts. Promotion of CeO₂ resulted in proper structural and good reducibility, which significantly increased the activity and the stability. With 3%~5% of CeO₂ , CeO₂-promoted Cu-ZnO catalysts showed highest activity and stability for the titled reaction.