VMoNb/CeO2 as an efficient catalyst for the gas-phase selective oxidation of toluene to benzaldehyde

Abstract

Gas-phase selective oxidation of toluene with air is a promising method for producing high-purity benzaldehyde, but the yields of existing catalysts are limited, so the development of more efficient catalysts is of great importance to the chemical industry. Herein VMoNb/CeO₂ was prepared and characterized by SEM, XRD, Raman, XPS, H₂-TPR, and NH₃-TPD. The introduction of Mo generated V–O–Mo “asymmetric lattice oxygen” and thus brought high activity. Nb moderated the acidity and oxygen vacancy so as to improve the selectivity. The VMoNb/CeO₂ catalyst showed very high catalytic activity at 500 °C, with 35% toluene conversion and 82% benzaldehyde selectivity at an air flow rate of 30 mL/min for V:Mo:Nb =2:5:0.8. This work could serve as a reference for designing mixed metal oxide catalysts for selective oxidation of aromatic hydrocarbons.