Highly efficient synchronized production of phenol and 2,5-dimethylfuran through a bimetallic Ni–Cu catalyzed dehydrogenation–hydrogenation coupling process without any external hydrogen and oxygen supply

Abstract

2,5-Dimethylfuran (DMF) and phenol are considered as one of the new-fashioned liquid transportation biofuels and a key motif for industrial chemicals, respectively. Herein, a highly efficient vapor-phase dehydrogenation–hydrogenation coupling process over bimetallic Ni–Cu alloy nanocatalysts was established for the synchronized production of phenol and DMF with unprecedentedly high yields (>97%) from two cyclohexanol (CHL) and biomass-derived 5-hydroxymethylfurfural (HMF) substrates, without any external hydrogen and oxygen supply. Systematic characterization and catalytic experiments revealed that the production of phenol went through a consecutive triple-dehydrogenation process from CHL, while HMF was simultaneously hydrogenated into DMF using active hydrogen species generated from the dehydrogenation process. The bimetallic Ni–Cu alloy nanostructures derived from Ni–Cu–Al layered double hydroxide precursors and strong metal–support interactions play important roles in governing the present coupling process. An appropriate Ni–Cu alloy nanostructure could greatly facilitate the dehydrogenative aromatization of CHL, thus significantly improving the selectivities to both phenol and DMF. Such an unparalleled efficient, eco-friendly and versatile coupling process for the synchronized production of various substituted phenols and DMF makes it practically promising for large-scale industrial applications in terms of green chemistry and sustainable development.