A series of Ni/γ-Al 2 O 3 and Ni−Mo/γ-Al 2 O 3 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-Al 2 O 3 catalyst could not only promote the dispersion of Ni particles but also weaken the interaction between NiO and the γ-Al 2 O 3 support. The effect of the calcination temperature on Ni−Mo/γ-Al 2 O 3 catalysts is mainly due to the enhancement of the interaction between Ni species and γ-Al 2 O 3 . The influence of the reduction temperature on the Ni−Mo/γ-Al 2 O 3 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-Al 2 O 3 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.

SiO2-modified γ-Al2O3 by chemical liquid deposition (CLD) was developed as a catalyst support for use in the aldol condensation of methyl acetate with formaldehyde to produce methyl acrylate. Cs/Al2O3 and Cs/Si–Al2O3 catalysts synthesized by incipient-wetness impregnation were characterized, and catalytic performance was evaluated. A correlation between structural features and acid–base properties has been established, and the effect of SiO2 deposition was investigated. The amount of strong acid sites was reduced, and the Brønsted acid sites were introduced onto the surface of Al2O3 with the deposition of SiO2. Moreover, interaction of Cs with the Brønsted acid sites generates the surface Si–O–Cs species which served to enhance selectivity to methyl acrylate. Conversion of methyl acetate was increased due to the formation of new basic sites following Cs incorporation. An excess of SiO2 and Cs hampered decomposition of the cesium nitrate, resulting in strong acid site formation and lower product yield. A 10Cs/1.2Si–Al2O3 composition has been established as optimal with a 4.8 times higher product yield in comparison with 10Cs/Al2O3. Lower activity in the case of the 10Cs/1.2Si–Al2O3 catalyst can be associated with carbon deposition during the reaction; activity can be regenerated after heat treatment at 400 °C.

In this study, a series of Ni10MoxAl composite metal oxide (Ni10MoxAl, NiO = 10 wt.%, x = 2.5, 5, 10, 15, 20 wt.%) catalysts with different Mo content were prepared by a solvothermal method using a water—ethanol system. By employing various characterization technologies, it was confirmed that the suitable amount of the Mo element can not only promote the dispersion of the Ni species but also inhibit the formation of the inactive NiAl2O4 phase. Consequently, the hydrogenation activity of the Ni10MoxAl catalysts was affected by the particle size of the active components and the amount of the NiAl2O4 phase. As a result, the Ni10Mo10Al catalyst showed the best catalytic performance on methyl acrylate hydrogenation, and the yield of methyl propionate can be increased from 53.7% to 89.5% at 100 °C and 1 MP H2, compared with the Ni10Mo10/γ–Al2O3 catalyst prepared by a traditional impregnation method. The stability of the Ni10Mo10Al catalyst was also investigated, and the catalyst can run stably for 23 h. The novel strategy adopted in this article provides a new direction for the preparation of high activity Ni–Mo catalysts.