Aerobic selective oxidation of alcohols using La1-xCexCoO3 perovskite catalysts

Abstract

The synthesis of porous perovskites with high and stable activity for alcohols oxidation using molecular oxygen as oxidant is reported. La1xCexCoO3 catalysts are prepared by a sol-gel method using methanol and ethylene glycol as complexing agents. Calcination at 600 C allows the formation of macro- and mesopores, in contrast to similar materials that often show a bulk structure. Catalytic tests show that La0.9Ce0.1CoO3 is highly active for benzyl alcohol oxidation with molecular oxygen, with both conversion and selectivity above 95% (60 min, 88 C, 1 atm). Further tests show that 94% of the original activity can be obtained after surface regeneration of the used catalyst. The good catalytic performance is explained by the presence of cerium, which is able to attract and release adsorbed oxygen on the oxygen vacancies. The electrons donated by alcohols improve the ability of oxygen vacancies to activate molecular oxygen into oxygen anions, which react with the alcohol and increase the reaction rate. A mechanism is proposed.