Deactivation of Cu/ZnO/Al2O3 Catalyst: Evolution of Site Concentrations with Time

The reforming of methanol is acknowledged as a convenient means to generate hydrogen for a PEFC due to the low temperature (<280 °C) at which the reaction occurs and the low CO content of the reformate. However, the catalyst is prone to deactivation in the upper range of its operating temperatures. This paper presents a method of analysis in which relative changes in site concentrations are deduced from a series of long-duration rate measurements. The sites involved in the reforming reaction are shown to evolve independently of each other. In particular, concentration of sites for hydrogen adsorption decline at a greater rate than those responsible for the adsorption of oxygenated species. A key process in the deactivation of the catalyst is the decrease in its capacity to adsorb and dissociate hydrogen.