Effects of Alkali Metal Oxide Additives on Cu/SiO2 Catalyst in the Dehydrogenation of Ethanol

Abstract

A series of Cu/SiO2 catalysts with various alkali metal oxide additives was investigated to elucidate the effects of additives on the catalytic properties of copper catalysts in the dehydrogenation of ethanol. The catalysts were prepared by the impregnation method and were characterized by X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption of CO2, and H2−N2O titration. The dehydrogenation reaction was carried out in a continuous-flow reactor at 300 °C under atmospheric pressure. The catalytic properties of the copper catalysts were strongly affected by the additives. The addition of alkali metal oxide increased the concentration of weak basic sites of the catalyst. The increase in turnover frequencies of the alkali-metal-oxide-modified catalysts was mainly due to the promotional effects of weak basic sites on Cu catalysts. KCu/SiO2 catalyst was very stable in the reaction process. The stabilities of NaCu/SiO2 and RbCu/SiO2 catalysts were similar to that of the unmodifie...