In-situ H+–H− pairs induced one-pot tandem acetalization–hydrogenolysis–hydrolysis of furfural to ethyl levulinate over NiCoP/LaPO4

Developing a cost-effective catalyst for the selective tandem conversion of furfural (FFA) to ethyl levulinate (EL) is important for synthesizing biofuels and fine chemicals from biomass. However, traditional catalysts prefer the hydrogenation-dehydration-hydrolysis pathway and are slow due to high activation energy requirement. Herein, a NiCoP/LaPO 4 catalyst was prepared via calcination of layered double hydroxide (LDH) precursor, followed by hydrogen reduction, and phosphating. When applied to the tandem of FFA for EL production, it exhibited a high selectivity of 90.1% at 160 °C under ethanol and water via acetalization–hydrogenolysis–hydrolysis route. Catalytic mechanism investigation indicated that in situ hydrogen spillover from NiCoP nanoparticles to the LaPO 4 support, leading to the formation of H + –H − pairs. These H + –H − pairs not only provide Brønsted acid sites to drive FFA acetalization and 2-ethoxymethyl furan (EMF) hydrolysis but also activate the C–O bonds of the key intermediate 2-diethoxymethyl furan (DEMF) via the S N 2 mechanism, markedly accelerating the hydrogenolysis step. Moreover, the NiCoP/LaPO 4 catalyst shows remarkable catalytic versatility for the synthesis of different alkyl levulinates from a range of alcohols (i.e., methanol, propanol, isopropanol, butanol and benzyl alcohol). This study presents an efficient bifunctional catalysis approach for complex tandem reaction pathways aimed at synthesizing alkyl levulinate by hydrogen spillover to generate transient H + –H − pairs.