Effect of Cu content on the surface and catalytic properties of Cu/ZrO2 catalyst for ethanol dehydrogenation

• Surface and catalytic properties of Cu/ZrO2 catalysts depend on the Cu content.
• The high selectivity to ethyl acetate for catalyst with Cu ≥ 10 wt.% is defined by the Cu+/Cu0 ratio and basic sites of O2−.
• The strong Lewis acid sites of cus Zr4+ cause the high selectivity to aldol condensation products.

ZrO2-supported Cu catalysts with different Cu content (5–30 wt.%) were prepared by impregnation method. The effect of Cu content on the structure, surface and catalytic properties of Cu/ZrO2 catalysts in the reaction of ethanol conversion was studied. The physicochemical characterization of the calcined and reduced samples was carried out by: N2 adsorption–desorption isotherms, N2O titration, XRD, XPS, TPR and DRFTS of CO adsorption. It was observed that the increase of Cu content leads to decrease of the apparent copper metal dispersion caused by the strong agglomeration of the metal particles. The selectivity to different reaction products was connected with the electronic properties of the catalysts defined by the copper particle size and the interface at metal-oxide support. The highest selectivity to ethyl acetate over samples with Cu content ≥10 wt.% was assigned to the high density of basic sites of O2− ions and more heterogeneous distribution of copper species (Cu0/Cu+) defined by DRIFTS of CO adsorption and XPS.

Evolution of the selectivity to propanone and to ethyl acetate as a function of the reaction temperature in ethanol dehydrogenation for Cu/ZrO2 catalysts with different Cu content: 5 (●); 10 (□); 20 (▶) and 30 wt.% (★).Figure optionsDownload high-quality image (100 K)Download as PowerPoint slide