Steam reforming of dimethyl ether over Cu-Ni/γ-Al_2O_3 bi-functional catalyst prepared by deposition- precipitation method

摘要

Cu-Ni/γ-Al_2O_3 catalysts with different metal contents for dimethyl ether steam reforming (DME SR) were prepared by the method of deposition-precipitation. Characterization of specific surface area measurement (BET), X-ray diffraction (XRD) and hydrogen temperature-programmed reduction (H_2-TPR) revealed that nickel improved the dispersion of copper, increased the interaction between copper and γ-Al_2O_3, and therefore, inhibited the sintering of copper. Ammonia temperature-programmed desorption (NH_3-TPD) showed that metal particles could occupy the acid sites, leading to the decrease in acid amount and acid strength of Cu-Ni/Y-Al_2O_3 catalyst. Kinetic measurements indicated that γ-Al_2O_3 is vital for DME SR and a higher content of γ-Al_2O_3 in catalyst was needed. The addition of nickel suppressed the water gas shift (WGS) reaction. Initial durability testing showed that the conversion of DME over Cu-Ni/γ-Al_2O_3 catalyst was always almost complete during the 30 h experimental reaction time. Therefore, Cu-Ni/γ-Al_2O_3 could be a potential DME SR catalyst for the production of hydrogen.