Aerobic Oxidation of Vanillyl Alcohol to Vanillin Over CeO ₂ ‐Co ₃ O ₄ Catalyst

Abstract

Abstract A promising CeO 2 ‐Co 3 O 4 (9 : 1 mole ratio based on oxides) non‐noble metal based mixed oxide catalyst was explored for selective oxidation of vanillyl alcohol with molecular oxygen to produce vanillin under atmosphere pressure. In particular, to enhance its efficiency, this catalyst was prepared by adopting different preparation methods namely, template assisted, coprecipitation with and without surfactant, wet‐impregnation, and solution combustion. The prepared catalysts were characterized by XRD, Raman, BET surface area, ICP‐OES, FE‐SEM, HR‐TEM, H 2 ‐TPR, and XPS. Among various catalysts investigated, the template assisted synthesized catalyst exhibited superior activity (100 % conversion and selectivity) and high stability. The better activity of this catalyst was found to be due to reduced crystallite size, high specific surface area (92 m 2 /g), more surface oxygen, and improved redox behaviour as confirmed from XRD, BET surface area, XPS, and H 2 ‐TPR analysis, respectively. The stability of the catalyst was tested by reusability test and was observed that there is not much decrease in the catalytic activity up to five cycles. Further, the catalytic activity was optimized by varying the reaction parameters such as time, solvent, temperature, and catalyst weight.