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The Ni/γ‐Al2O3, Nix‐Fey/γ‐Al2O3 and Fe/γ‐Al2O3 catalysts are prepared by impregnation method, and the influence of nNi/nFe on the performances of the prepared catalysts for the methyl laurate hydrodeoxidation (HDO) was evaluated. The prepared catalysts and precursors were characterized by BET, H2‐TPR, XRD, and H2‐TPD, which confirmed the existence of NiFe alloy is advantageous to improve the catalytic activity, and the synergistic effect between Ni and Fe was elucidated. The catalytic properties of the studied Nix‐Fey/γ‐Al2O3 catalysts with low Fe content was significantly worse than that of monocomponent Ni/γ‐Al2O3 catalyst, due to the migration and agglomeration of highly dispersed Ni0 species on the corresponding catalyst surface. The introduction of Fe species had significant influence on the HDO performances and product selectivity of the Ni‐based catalyst. The higher Fe content can promote the main reaction path from hydrodecarbonylation/hydrodecarboxylation to hydrodeoxygenation, which results in the high C12 alkane selectivity on the corresponding catalysts and inhibits the cracking reaction. The bimetallic Ni3‐Fe7/γ‐Al2O3 catalyst had the best methyl laurate hydrogenation performances. The conversion of methyl laurate was 93.3 % and the selectivity of alkane compounds could reach 90 % on the Ni3‐Fe7/γ‐Al2O3 catalyst at the reaction temperature of 340 °C. [ABSTRACT FROM AUTHOR]

Ni component can be effectively introduced into CeO2 by a soft template method to prepare porous NiCe composite catalysts. The reducibility of the catalyst precursors was studied by H2‐TPR. The physicochemical properties of the prepared NiCe composite catalysts were characterized by XRD, quasi in‐situ XPS, BET and TEM. And the catalytic performances of the corresponding NiCe composite catalysts was evaluated by CO2 catalytic hydrogenation. The synergistic effect of Ni and Ce species can significantly improve the reducibility of the precursors to form CO2 hydrogenation active sites in the corresponding NiCe composite catalysts. The morphology, pore structure, specific surface area, crystallinity and content of metal Ni species of the prepared NiCe composite catalysts were significantly affected by nNi/nCe ratio, which can affect the CO2 catalytic hydrogenation performances of NiCe composite catalysts. The synergistic effect of Ni and Ce species can also promote the formation of NiCe composite catalyst nanoparticles with small particle size about 5–10 nm. The developed mesoporous structure and high specific surface area can be formed in the prepared NiCe composite catalysts. The NC3 catalyst with a nNi/nCe ratio of 3.0 showed the best CO2 hydroreduction performances and use stability. When the reaction temperature was 300 °C, the CO2 conversion and CH4 selectivity can reach 85.6% and 100%, respectively. Even if the reaction temperature rises to 340 °C, the CO2 conversion and CH4 selectivity can be maintained at 83.7% and 100% in the continuous reaction of 600 min, respectively. [ABSTRACT FROM AUTHOR]

Pd/CeO2 catalysts with different metallic Pd loading were synthesized by impregnation method. The physicochemical properties of prepared Pd/CeO2 catalysts and corresponding precursors were studied by XRD, XPS, H2-TPD and H2-TPR. Moreover, the catalytic performance of the Pd/CeO2 catalysts was investigated via gas phase benzene hydrogenation reaction at the temperature of 100–200 °C under atmosphere pressure. Results show that the catalytic performance of prepared Pd/CeO2 catalysts is directly related to the metallic Pd content. The amounts of active metallic Pd and adsorbed-desorbed hydrogen species on Pd/CeO2 catalysts increase with the increasing metallic Pd loading from 1.0 to 3.0%, while the numbers of them are slightly reduced on Pd/CeO2(3.5) catalyst. Furthermore, metallic Pd is highly dispersed on the nano-CeO2 supports, therefore, the prepared Pd/CeO2 catalysts present good gas phase benzene catalytic hydrogenation performance. At 200 °C, the benzene conversion over the Pd/CeO2 catalysts with different metallic Pd loading follows the rule: Pd/CeO2(3.0) > Pd/CeO2(3.5) > Pd/CeO2(2.5) > Pd/CeO2(2.0) > Pd/CeO2(1.5) > Pd/CeO2(1.0), corresponding values are 94.3, 96.4, 89.9, 82.8, 72.7, 42.6 and 94.3%. And the cyclohexane selectivity is 100% on all prepared Pd/CeO2 catalysts. [ABSTRACT FROM AUTHOR]