TAP reactor study of the deep oxidation of propane using cobalt oxide and gold-containing cobalt oxide catalysts

A transient reactor study of the oxidation of propane to CO2 on gold-free and gold-doped CoOx catalysts has been carried out. It has been demonstrated that the presence of gold markedly promotes the catalytic reactivity of cobalt oxide in the total oxidation of propane. Both catalysts oxidised propane directly to CO2 via a Mars-Van Krevelen mechanism, and this was confirmed using isotopically labelled oxygen experiments. The increased activity of the gold catalyst is related to the faster reoxidation of the cobalt oxide when gold is present in the catalyst, since the reaction step in which the catalyst is reduced, due to propane oxidation, is similar for both catalysts. The faster reoxidation of the gold catalyst can be linked to the higher concentration of oxygen vacancies in the catalysts, determined by O-2 uptake results obtained from transient studies in the presence of oxygen. (C) 2009 Elsevier B.V. All rights reserved.