Oxidation catalysis on YBa₂Cu₃O_6+x

Abstract

Mild oxidation catalysts are used to product a wide range industrial chemicals from hydrocarbons, whereas deep oxidation catalysts yield CO₂ and are becoming important in the cleaning of emissions from combustion of carbonaceous fuels. Here we report on a catalyst¹ that facilitates both mild and deep oxidation of toluene in the presence of molecular oxygen and ammonia. At low partial pressures of O₂a YBa₂Cu₃O_6+x catalyst is very active in the formation of benzonitrile, but at higher O₂ partial pressures it preferentially catalyses formation of CO₂. This sharp transition in product selectivity is reversible and occurs at a defined partial pressure of O₂. At transition the bulk compostition of the catalyst is close to YBa₂Cu₃O₆ (x≈0). Increasing the content of lattice oxygen (x > 0) makes the catalyst selective for CO₂ formation.