Kinetics of deactivation on Cu/ZnO/Al₂O₃ methanol synthesis catalysts

Deactivation behavior is an important topic in catalyst development. In case of methanol synthesis the conventional Cu/ZnO/Al₂O₃ system is commonly known to be prone to sintering, however, information about the structural development during deactivation or the sintering mechanism(s) are scarce. We present a systematic deactivation study on three different Cu/ZnO/Al₂O₃ catalysts which are aged under constant conditions and periodically analyzed using kinetic measurements and N₂O chemisorption. A power law model for the catalyst activity with time on stream is derived. Furthermore it is found, that the presence of water provokes a steep loss in active surface area and specific activity. Also, the TEM particle size distributions generated during the aging treatment are evaluated and discussed.