Efficient Promotional Effects of Mo on the Catalytic Hydrogenation of Methyl Acrylate over Ni-Based Catalysts under Mild Conditions

A series of Ni/γ-Al₂O₃ and Ni–Mo/γ-Al₂O₃ catalysts were prepared and evaluated for the hydrogenation of methyl acrylate to methyl propionate in a fixed-bed reactor. Physicochemical characterizations of these catalysts were carried out with Brunauer–Emmett–Teller analysis, X-ray diffraction, UV–vis diffuse reflectance spectroscopy, Raman spectroscopy, hydrogen temperature programed reduction, X-ray photoelectron spectroscopy, and transmission electron microscopy. It was noticed that Mo loaded onto the Ni/γ-Al₂O₃ catalyst could not only promote the dispersion of Ni particles but also weaken the interaction between NiO and the γ-Al₂O₃ support. The effect of the calcination temperature on Ni–Mo/γ-Al₂O₃ catalysts is mainly due to the enhancement of the interaction between Ni species and γ-Al₂O₃. The influence of the reduction temperature on the Ni–Mo/γ-Al₂O₃ catalysts, as well as the reaction conditions, was also studied in detail. As a result, this hydrogenation process could be efficiently promoted on the optimal 10Ni–10Mo/γ-Al₂O₃ catalyst with the highest yield of 94% and selectivity of 99.9%, and no deactivation behavior was observed after 130 h time-on-stream at 100 °C and 1.0 MPa.