Stability of copper catalysts for methanol synthesis

Abstract

Catalysts are of great importance for the chemical industry and the production of fuels and chemicals. These materials become less efficient over time. In this thesis the stability of copper catalysts during methanol synthesis was studied. The copper particles in these catalysts grow during the reaction, leading to deactivation of the catalyst. The particles grow due to two mechanisms: diffusion of the particles over the support material and subsequent coalescence, and Ostwald ripening. In this thesis, catalysts with different properties were synthesized, enabling to determine the influence of these properties on the deactivation rate. A mathematical model was developed to describe the contributions of the individual deactivation mechanisms. The deactivation of copper catalysts can be predicted more accurately, with the aid of this model. Moreover, catalysts with a cage-like support material were prepared. With this method the copper particle could be isolated in the cages, improving the stability. In addition, the activity of copper catalysts as a function of particle size was investigated.