Methanol synthesis revisited: The nature of the active site of Cu in industrial Cu/ZnO/Al2O3 catalyst and Cu-Zn synergy

Abstract

In this report, we shed an illuminating light on the recent developments on the nature of active site in copper and the microstructural analysis (based on HRTEM/EDX/X-ray techniques) of the Cu/ZnO methanol catalyst. We investigate/analyze two phenomena frequently invoked to explain the key promotional role of Zn in Cu-based methanol catalysts: Formation of a near-surface Cu-Zn alloy by a substitutional displacement of Cu atoms by Zn, especially at the perimeter interface and polarization of electron densities, which can lead additional charge transfer from Zn, from ionic vacancies in the ZnO lattice. With these 2 mechanisms and the ubiquitous role of ZnO as a structural promoter, we explain how these results can be used to design better/more active catalysts from the standpoint of chemical kinetics.