Synergistic Effect of Oxygen Vacancies and Ni Species on Tuning Selectivity of Ni/ZrO2 Catalyst for Hydrogenation of Maleic Anhydride into Succinic Anhydride and γ-Butyrolacetone

Abstract

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.

Tuning Selectivity of Maleic Anhydride Hydrogenation Reaction over Ni/Sc-Doped ZrO2 Catalysts

“…The stronger interaction further resulted in the decrease of the oxygen vacancies concentration on surface of ZrO2-based supported nickel catalysts, which probably because a small amount of nickel species entered into oxygen vacancies. This result is consistent with our previous study [17], in that the strong interaction between nickel species and ZrO2 support would lead to a small amount of nickel species entering into the tetragonal ZrO2 lattice, and in HRTEM it had been clearly seen that the lattice spacing of the tetragonal ZrO2 increased from 0.29 nm to 0.30 nm, thereby leading to a significant decrease of the surface oxygen vacancies concentration. Based on the above results, it can be concluded that the introduction of Sc 3+ into ZrO2 changes the surface structure of ZrO2-based supports.…”

“…In our aforementioned earlier article [17], the Raman, H2-TPR, and XPS characterization results hinted that there was a relationship between the electronic properties of surface oxygen vacancies on the Ni/ZrO2 catalysts and the surface structure of the ZrO2 supports. However, due to a comparison of only two ZrO2-supported nickel catalysts in the previous article, it was difficult for us to reach an MA is a five-membered ring molecule structure, with C=C, C=O, and C-O-C functional groups.…”

“…In our aforementioned earlier article [17], the Raman, H 2 -TPR, and XPS characterization results hinted that there was a relationship between the electronic properties of surface oxygen vacancies on the Ni/ZrO 2 catalysts and the surface structure of the ZrO 2 supports. However, due to a comparison of only two ZrO 2 -supported nickel catalysts in the previous article, it was difficult for us to reach an unambiguous conclusion concerning the relationship between the surface structure of the ZrO 2 support and the electronic properties of surface oxygen vacancies on the Ni/ZrO 2 catalysts, as well as the selective hydrogenation performance of ZrO 2 -supported nickel catalyst.…”

“…Our research group previously investigated the maleic anhydride hydrogenation performances of Ni/TiO 2 (TiO 2 supports with different crystal structure, rutile and anatase) and Ni/CeO 2 catalysts [15,16], the result showed that the oxygen vacancies on surface of Ni/TiO 2 (anatase) and Ni/CeO 2 catalysts might be contributed to the higher C=O hydrogenation activity. Further, in our recent study [17], two ZrO 2 supports, with each having monoclinic and tetragonal mixed crystalline phases but differing in tetragonal content, were prepared. In MA hydrogenation reaction, the two ZrO 2 -supported nickel catalysts exhibited completely different C=O hydrogenation activities.…”

Advances in Heterocatalysis by Nanomaterials

“…Zhao et al [21] produced ZrO 2 nanoparticles, ZrO 2 (P) and ZrO 2 (H), with different tetragonal phase content (higher in the former), which was used as support for the preparation of 10 wt % Ni/ZrO 2 catalysts via impregnation. The catalysts were characterized by means of XRD, Raman, H 2 -TPR, XPS, and H 2 -TPD techniques, and their catalytic performance was evaluated under the hydrogenation of maleic anhydride toward succinic anhydride and γ-butyrolacetone.…”