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A series of Sc-doped ZrO2 supports, with Sc2O3 content in the range of 0 to 7.5% (mol/mol), were prepared using the hydrothermal method. Ni/Sc-doped ZrO2 catalysts with nickel loading of 10% (w/w) were prepared using impregnation method, and characterized with the use of XRD, Raman, H2 temperature-programmed reduction (H2-TPR), H2 temperature-programmed desorption (H2-TPD), XPS, and in situ FT-IR techniques. The catalytic performances of Ni/Sc-doped ZrO2 catalysts in maleic anhydride hydrogenation were tested. The results showed that the introduction of Sc3+ into ZrO2 support could effectively manipulate the distribution of maleic anhydride hydrogenation products. γ-butyrolactone was the major hydrogenation product over Sc-free Ni/ZrO2 catalyst with selectivity as high as 65.8% at 210 °C and 5 MPa of H2 pressure. The Ni/Sc-doped ZrO2 catalyst, with 7.5 mol% of Sc2O3 content, selectively catalyzed maleic anhydride hydrogenation to succinic anhydride, the selectivity towards succinic anhydride was up to 97.6% under the same reaction condition. The results of the catalysts' structure–activity relationships revealed that there was an interdependence between the surface structure of ZrO2-based support and the C=O hydrogenation performance of the ZrO2-based supported nickel catalysts. By controlling the Sc2O3 content, the surface structure of ZrO2-based support could be regulated effectively. The different surface structure of ZrO2-based supports, resulted in the different degree of interaction between the nickel species and ZrO2-based supports; furthermore, the different interaction led to the different surface oxygen vacancies electron properties of ZrO2-based supported nickel catalysts and the C=O hydrogenation activity of the catalyst. This result provides new insight into the effect of ZrO2 support on the selective hydrogenation activity of ZrO2-supported metal catalysts and contributes to the design of selective hydrogenation catalysts for other unsaturated carbonyl compounds. [ABSTRACT FROM AUTHOR]

ZrO2 nanoparticles, ZrO2 (P) and ZrO2 (H), with different tetragonal phase contents, were prepared. ZrO2 (P) possessed higher tetragonal phase content than ZrO2 (H). Ni/ZrO2 catalysts (10% (w/w)), using ZrO2 (P) and ZrO2 (H) as supports, were prepared using an impregnation method, and were characterized using XRD, Raman, H2-TPR, XPS, and H2-TPD techniques. Their catalytic performance in maleic anhydride hydrogenation was tested. The Ni/ZrO2 (P) catalyst exhibited stronger metal-support interactions than the Ni/ZrO2 (H) catalyst because of its higher number of oxygen vacancies and the low-coordinated oxygen ions on its surface. Consequently, smaller Ni crystallites and a higher C=C hydrogenation activity for maleic anhydride to succinic anhydride were obtained over a Ni/ZrO2 (P) catalyst. However, the C=O hydrogenation activity of Ni/ZrO2 (P) catalyst was much lower than that of the Ni/ZrO2 (H) catalyst. A 43.5% yield of γ-butyrolacetone was obtained over the Ni/ZrO2 (H) catalyst at 210 °C and 5 MPa of H2 pressure, while the yield of γ-butyrolactone was only 2.8% over the Ni/ZrO2 (P) catalyst under the same reaction conditions. In situ FT-IR characterization demonstrated that the high C=O hydrogenation activity for the Ni/ZrO2 (H) catalyst could be attributed to the surface synergy between active metallic nickel species and relatively electron-deficient oxygen vacancies. [ABSTRACT FROM AUTHOR]