Ni-Al/CoOx-catalyzed hydrodeoxygenation of 5-hydroxymethylfurfural into 2,5-dimethylfuran at low temperatures without external hydrogen

Catalytic hydrodeoxygenation of 5-hydroxymethylfurfural into 2,5-dimethylfuran has received great interest in recent years. In this work, a ternary Ni-Al/CoOx-1 catalyst was fabricated, which provided 96% yield of DMF from in situ hydrodeoxygenation of HMF under mild reaction conditions. XRD, TEM and TPR revealed that the addition of Al to the Ni-Co bimetallic system could make the structure more stable and improve the dispersion of Ni and Co species. XPS, CO-DRIFTS and EPR verified that an enhanced electron transfer from Co species to Ni occurred on Ni-Al/CoOx-1. Reaction mechanism studies unraveled that the Al addition results in promoting in situ H 2 production from 2-propanol and accelerating the aldehyde group hydrogenation to a hydroxymethyl group and the subsequent hydrogenolysis into a methyl group, due to the formation of a charge separated metal-couple-site (Ni δ − -Co δ + ) and stronger Lewis acid sites in Ni-Al/CoOx-1. In addition, this ternary Ni-Al/CoOx-1 catalyst exhibits superior recyclability without significant loss of activity for 7 cycles. Catalytic hydrodeoxygenation of 5-hydroxymethylfurfural into 2,5-dimethylfuran has received great interest in recent years.