Nitrogen-doped carbon-decorated copper catalyst for highly efficient transfer hydrogenolysis of 5-hydroxymethylfurfural to convertibly produce 2,5-dimethylfuran or 2,5-dimethyltetrahydrofuran

Currently, highly efficient transformation of abundant and low-cost renewable raw biomass into high-quality biofuels and important chemicals is one of the most promising solutions to the current energy crisis, rapid consumption of fossil resources, increasing emission of greenhouse gases and serious environmental pollution. Here, convertible production of promising 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF) biofuels was achieved successfully via green catalytic transfer hydrogenolysis of biomass-derived 5-hydroxymethylfurfural (HMF) using a nitrogen-doped carbon (NC)-decorated copper-based catalyst with cyclohexanol as hydrogen source. DMF or DMTHF with high yield of 96.1% or 94.6% was produced convertibly through simply modulating reaction time. Extensive characterizations revealed that appropriate surface base sites on the catalyst could efficiently promote the activation of alcohol hydroxyl in cyclohexanol and the subsequent release of active hydrogen species, while highly dispersed surface Cu0 nanoparticles and electrophilic Cu+ species were beneficial to the hydrogen transfer and the activation of both the carbonyl group and the hydroxyl group in HMF, respectively. Moreover, as-fabricated NC-decorated Cu-based catalyst presented high stability without obvious loss of catalytic performance after five consecutive cycles, due to the strong interaction between the support and active metal species. Such non-noble metal catalyst has a promising industrial application in the production of valuable biomass fuels.