Some insight into the effects of oxygen diffusion in the reduction kinetics of ceria

The aim of this paper is to discuss the main features of the temperature-pr ogrammed reduction of high-surface-area ceria in the low-temperature range (T < 900 X) with particular emphasis on the role of oxygen diffusion. By ma king use of a cell model for the reaction/diffusion process, it is shown th at the observed kinetics is not influenced by oxygen diffusion within the l attice for the values of oxygen diffusivity available for ceria. This resul t enables us to develop a simple and spatially uniform kinetic model for ce ria reduction. The effects of sintering and surface area are also briefly a ddressed.