Effect of Ce doping on the structure–activity relationship of MoVOx composite metal oxides

Abstract

A series of Ce-doped MoVO_x composite metal oxide catalysts were prepared by the rotary evaporation method. The effects of Ce doping ratio on the crystal phase composition, morphology and surface properties of the catalysts were investigated. The results show that the crystal phase composition of samples with different Ce doping content is also obviously different. When the doping amount is small, V_0.95Mo_0.97O₅ is the main crystal phase, while MoO₃ is dominant when the doping amount is large. The Ce-doped catalyst showed obvious rod-shaped morphology and its average single point pore diameter and the number of acidic sites increased. Compared to the un-doped MoVO_x, the pore size of the sample synthesized at a Mo/Ce atomic ratio of 10/1 exhibited an increase of 41.11 nm. In addition, the effect of Ce doping on the catalytic performance of MoVO_x was investigated with the selective oxidation of benzyl alcohol as a probe reaction. After doping, the MoVO_x catalyst showed improved benzyl alcohol conversion and selectivity to benzaldehyde. At a Mo/Ce atomic ratio of 10/1, the conversion rate of benzyl alcohol reaches 83.26%, which is 64.56% higher than that without doping, and the highest product yield can reach 76.47%.