Stable ethanol synthesis via dimethyl oxalate hydrogenation over the bifunctional rhenium-copper nanostructures: Influence of support.

[Display omitted] • Supported ReCu catalysts were synthesized for DMO hydrogenation to ethanol. • The Re 2 Cu 5 /ZrO 2 catalyst exhibited the best catalytic performance. • The molar ratio of Cu0 and Cu+, reduction degree and copper particle size play the pivotal role. • Good stability of Re 2 Cu 5 /ZrO 2 catalyst. Addition of oxophilc rhenium to decorate small copper nanoparticles has been validated to be an efficient method to prepare a low-copper catalyst for the direct synthesis of ethanol via dimethyl oxalate (DMO) hydrogenation process, and herein we investigated the impact of supports on the catalytic performance of ReCu catalysts. A series of materials including activated carbon (AC), Al 2 O 3 , SiO 2 , TiO 2 and ZrO 2 were utilized as the support and as prepared Re 2 Cu 5 catalysts were evaluated. The results exhibited that the Re 2 Cu 5 /ZrO 2 catalyst possesses the highest DMO hydrogenation activity and ethanol yield (∼93%), which may be due to its lowest Cu0/Cu+ ratio (0.13), smallest Cu particle size (∼0.84 nm) a relative high reduction degree (59%). The CO adsorption behavior characterized by in si tu IR spectroscopy showed that a strong metal-support interaction creates an electron deficient environment of Cu nanoparticle, resulting in a lower Cu0/Cu+ ratio that enhances the activation of C O bond in the DMO molecular. [ABSTRACT FROM AUTHOR]