Preparation of MgO-Supported Cu2O Catalyst and Its Catalytic Properties for Cyclohexanol Dehydrogenation

To obtain a more effective catalyst for the dehydrogenation of cyclohexanol to cyclohexanone, the MgO-supported Cu2O catalyst was prepared by chemical reduction combined with impregnation using MgO as the support and hydrazine hydrate as the reducing agent. The effects of the preparation conditions on the catalytic properties of the catalyst were studied, and the catalyst was characterized by N2 adsorption, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Auger electron spectroscopy, and temperature-programmed reduction. Cu2O is reduced to Cu0 when the amount of N2H4·H2O used is high. With increasing amount of NaOH used, catalyst particles congregate and the specific surface area of catalyst decreases. The catalyst activity for dehydrogenation of cyclohexanol reaches the maximum at a molar ratio Cu2+:N2H4·H2O:NaOH of 1:1:2. The catalyst reduced by N2H4·H2O is composed of only Cu+, whereas the traditional Cu/MgO catalyst contains Cu0 and a little Cu+. Because Cu+ is more active than Cu0, the activity of the Cu2O/MgO catalyst is much higher than that of the traditional Cu/MgO catalyst.