Catalytic behavior and surface chemistry of Copper/ZnO/Al2O3 catalysts for the decomposition of 2-propanol

CuO/ZnO/Al2O3 samples (1 and 4 Cu atoms and 1, 5, 15, and 30 Zn atoms per 100 Al atoms, respectively) have been tested as catalysts for the decomposition of 2-propanol. The samples were pretreated in a controlled way in hydrogen or in the reaction medium in order to have a known surface content of Cu(0). Below 440 K the samples showed only dehydrogenating activity. A linear relationship was found between the rate constant and the surface area of zero-valent copper. It is hence proposed that surface Cu(0) species are responsible for the dehydrogenation. The higher values of turnover frequency for the present system in comparison with the values previously found on CuO/Al2O3 enable a proposal to be made for the role of the zinc in the activity of the Cu(0) species. The beneficial effect of the zinc on the reducibility of Cu2+ ions and a reduction mechanism are also discussed. © 1992