Oxidation of CO on tantalum, niobium, and niobium oxide

It was found experimentally that the catalytic activity of Ta and Nb in the reaction between CO and O2 increases with the activation energy after a thermogradient treatment of the catalysts in the reaction medium. A similar effect was not observed for niobium oxide; in this case, the reaction proceeded at two types of site with different activation energies Ea1 ~ 15 kJ/mol and Ea2 ~ 100 kJ/mol. The values of Ea for the reactions on Nb and Ta before and after activation were close to the Ea1 and Ea2 values, respectively. The thermal treatment of Ta in a vacuum, CO, and O2 was shown to influence adsorption of CO.