A combined experimental and theoretical study on ethanol conversion to propylene over Y/ZrO2 catalyst.

ZrO 2 -based catalysts doped with Y were prepared by co-precipitation method. The effect of yttrium modification on the selective conversion of bio-ethanol to propylene over ZrO 2 catalysts was investigated. The physical and chemical properties of the catalysts were characterized by N 2 adsorption-desorption method, temperature programmed desorption and X-ray diffraction. The maximum yield of propylene reached 44.0% over 0.03Y/ZrO 2 catalyst. A coordination of acid-base properties accounts for the remarkable improvement of reaction activities over Y-doped ZrO 2 catalysts in this investigation. On the basis of calculation results, it can be concluded that significant charge transfer occurs as a result of introduction of Y or O-vacancy. The adsorption of ethanol and propylene on perfect t-ZrO 2 (1 0 1), defect t-ZrO 2 (1 0 1) and Y/ZrO 2 (1 0 1) surfaces were investigated with density functional theory (DFT). The adsorption for ethanol on Y/ZrO 2 (1 0 1) and defect t-ZrO 2 (1 0 1) surfaces are more stable than that on perfect t-ZrO 2 (1 0 1). On the defect t-ZrO 2 (1 0 1) surface, ethanol dominantly absorbs at the O-vacancy site, indicating that O-vacancy becomes the favorable adsorption site. On the Y/ZrO 2 (1 0 1) and defect t-ZrO 2 (1 0 1) surfaces, the adsorption energy of propylene decreases, which makes propylene desorb quickly after formation. [ABSTRACT FROM AUTHOR]