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Effect of the ZrO₂ phase on the structure and behavior of supported Cu catalysts for ethanol conversion

Sato, A.G., Volanti, D.P., Meira, D.M., Damyanova, S., Longo, E., Bueno, J.M.C.
Journal of catalysis 2013 v.307 pp. 1-17
X-ray photoelectron spectroscopy, acetaldehyde, active sites, catalysts, copper, electron transfer, ethanol, ethyl acetate, oxygen
The effect of amorphous (am-), monoclinic (m-), and tetragonal (t-) ZrO₂ phase on the physicochemical and catalytic properties of supported Cu catalysts for ethanol conversion was studied. The electronic parameters of Cu/ZrO₂ were determined by in situ XAS, and the surface properties of Cu/ZrO₂ were defined by XPS and DRIFTS of CO-adsorbed. The results demonstrated that the kind of ZrO₂ phase plays a key role in the determination of structure and catalytic properties of Cu/ZrO₂ catalysts predetermined by the interface at Cu/ZrO₂. The electron transfer between support and Cu surface, caused by the oxygen vacancies at m-ZrO₂ and am-ZrO₂, is responsible for the active sites for acetaldehyde and ethyl acetate formation. The highest selectivity to ethyl acetate for Cu/m-ZrO₂ catalyst up to 513K was caused by the optimal ratio of Cu⁰/Cu⁺ species and the high density of basic sites (O²⁻) associated with the oxygen mobility from the bulk m-ZrO₂.