Lanthanum-doped CuMn composite oxide catalysts for catalytic oxidation of toluene

Abstract

Abstract CuMn mixed oxides catalysts doped with La were prepared following a co-precipitation method and used for the catalytic oxidation of toluene. Catalysts properties of the catalysts were investigated by X-ray diffraction, N2 adsorption/desorption, scanning electron microscopy, H2-temperature-programmed reduction (H2-TPR), O2-temperature-programmed desorption (O2-TPD) and X-ray photoelectron spectroscopy techniques. Characterization data reveal that the phase change and decrease in crystallinity of the La-doped catalysts increase the number of oxygen vacancies. Improvements in reducibility and an increase in the amount of chemisorbed oxygen of the La-doped catalysts were also verified by H2-TPR and O2-TPD. The activity of the CuMn mixed oxides catalysts is significantly improved by the addition of a nominal amount of La. The CuMn/La-4 mol% catalyst exhibits the best catalytic activity, with a 90% conversion temperature of 255\xa0°C, attributed to a high Mn3+ratio, superficial chemisorbed oxygen, and high surface area. This study indicates La to be a promising dopant for Cu Mn catalysts toward toluene oxidation.