CuZnCoO_x multifunctional catalyst for in situ hydrogenation of 5-hydroxymethylfurfural with ethanol as hydrogen carrier

Catalytic in situ hydrogenation of 5-hydroxymethylfurfural (5-HMF) to 2,5-dimethylfuran (DMF) has received a great interest in recent years. However, the issue of the consumption of expensive hydrogen donors, such as secondary alcohols, limits its applications. In this work, a ternary CuZnCoO_x catalyst, exhibiting a 99% yield of DMF from in situ hydrogenation of 5-HMF with ethanol as economical hydrogen donor, is developed. High resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS-mapping), X-ray diffraction (XRD) and temperature programmed reduction (TPR) reveal the synergy effect of each components. Reaction mechanism studies unravel the CoO_x results in promoting in situ H₂ production from ethanol, the zinc oxide accelerates the aldehyde group ([sbnd]CHO) hydrogenation to hydroxymethyl group ([sbnd]CH₂OH) and the formation of Cu-Co alloy significantly facilitate the hydrogenation of 5-HMF. Additionally, this ternary CuZnCoO_x catalyst exhibits superior recyclability without losing any activity during 6 cycles experiment.