CO Oxidation Over Ceria-Based Catalysts: Comparison of Single and Binary Metal Oxides

Abstract

Wet air oxidation (WAO) of lignocellulosic biomasses is a promising route for the production of renewable and valuable compounds. In this work, acetovanillone (AV) was selected as lignin model molecule in order to investigate its behavior under the WAO reaction conditions. The experiments were carried out in a pressurized 50 ml batch reactor loaded with NaOH 2M as solvent, the reaction takes 1 h with temperatures ranging from 130 to 190 °C and air pressures between 5 and 30 bar. The perovskite-type mixed oxide LaFeO₃ was synthetized and used as heterogeneous catalyst in order to improve the activation of molecular oxygen. Vanillin yield resulted to benefit from high reaction temperature showing a maximum carbon yield of 22%, instead the formation of carboxylic acids from the oxidative degradation of AV largely benefits from high pressure of air, exhibiting an overall carbon yield of 35%. The produced compounds include oxalic, glycolic, lactic, malonic, and levulinic acid.