Modulating the electronic structure of Co-Ni bimetal oxides on mesoporous silica for promoting selective oxidation of alcohol

Abstract

The selective oxidation of alcohols by transition-metal-based catalysts provides a green route for the production of aldehydes. In this paper, mesoporous SBA-15 supported bimetallic NixCoy oxides were synthesized for the catalytic oxidation of alcohol using oxygen as the sole oxidant. The catalytic activity was highly related to the metal composition, of which the Ni1Co4/SBA-15 catalyst showed the best catalytic performance with high benzyl alcohol conversion of 96.2% and benzaldehyde selectivity of 98.3%. It was proposed that the electronic structure of the NixCoy/SBA-15 catalysts can be modulated by Ni/Co ratio, and high Co3+/Co2+ and Ni3+/Ni2+ ratios promoted the catalyst activity. Compared to the NixCoy nanocatalysts obtained by removing SBA-15 support, the NixCoy/SBA-15 exhibited a better benzyl alcohol oxidation performance, suggesting a diffusion enhancement by the mesoporous structure of SBA-15 support.