Deactivation and regeneration of the commercial Cu/ZnO/Al2O3 catalyst in low-temperature methanol steam reforming

Cu-based catalysts with excellent activity at low temperatures are widely used for methanol steam reforming (MSR) but suffer from deactivation problems. The present work aims to elucidate the deactivation and regeneration mechanisms of the commercial Cu/ZnO/Al2O3 catalyst in low temperature MSR. By employing a series of (quasi) in situ characterization methods, it is found that the deactivation of the catalyst at a high weight hourly space velocity (WHSV) and a low reaction temperature is mainly due to the poisoning of Cu species associated with surface-oxygenated species with less Cu sintering, rather than carbon deposition, and strong metal-support interaction (SMSI). An in situ regeneration method was developed for the deactivated commercial Cu/ZnO/Al2O3 catalyst via the simultaneous supply of O-2. It is shown that the addition of O-2 (>= 1 vol%) can reverse the deactivation caused by surface-oxygenated poisoning due to the weak interaction between formed surface copper oxide and surface-oxygenated species, facilitating their desorption, but not deactivation caused by sintering, thereby partially restoring the catalytic activity.