INFLUENCE OF SURFACE OXYGEN VACANCIES ON THE CATALYTIC ACTIVITY OF COPPER-OXIDE .2. OXIDATION OF METHANE

The role of surface oxygen vacancies in the activity of a copper oxide on alumina catalyst for the oxidation of methane was investigated using temperature-programmed reduction and continuous flow experiments. It was established that the initial reactivity of the catalyst towards reduction with methane depends on the presence of oxygen vacancies. During reduction, the influence of the vacancies is diminished by fast diffusion of subsurface oxygen to the surface and by water formed during the oxidation. The water and the subsurface oxygen are responsible for blocking adsorption sites for methane. The catalytic activity thus does not vary markedly with the total number of oxygen vacancies.