Ceria Promoted Cu-Ni/SiO(2) Catalyst for Selective Hydrodeoxygenation of Vanillin

[Image: see text] A ceria (CeO(2)) promoted Cu-Ni bimetallic catalyst supported on SiO(2) (Cu-Ni/CeO(2)-SiO(2)) was prepared and evaluated for catalytic hydrodeoxygenation (HDO) of vanillin. Silica supported monometallic Cu and Ni catalysts and bimetallic Cu-Ni catalyst (Cu/SiO(2), Ni/SiO(2), and Cu-Ni/SiO(2)), without a ceria promoter, were also synthesized and tested for the same application. The highest conversion of vanillin was achieved with the Cu-Ni/CeO(2)-SiO(2) catalyst. Vanillyl alcohol was the sole product in the initial 2 h, followed by the formation of 2-methoxy-4-methylphenol, which was observed. Characterization of the synthesized catalysts revealed the presence of overlapping crystalline phases of CuO, NiO, and CeO(2) on the Cu-Ni/CeO(2)-SiO(2) surface. We extended our study to find out the results of using CeO(2) as the support of the Cu-Ni bimetallic catalyst (Cu-Ni/CeO(2)). Partial incorporation of Cu and Ni cations into the ceria lattice took place, leading to the decrease of specific surface area and a concomitant compromise in the conversion. In the case of the Cu-Ni/CeO(2)-SiO(2) catalyst, the higher conversion was accredited to the facile formation of Cu(+) active centers by the synergistic interaction between Ce(+4)/Ce(+3) and Cu(+2)/Cu(+) redox couples and the incorporation of oxygen vacancies on the catalyst surface.