γ-valerolactone (GVL) is an important value-added chemical with potential applications as a fuel additive, a precursor for valuable chemicals, and polymer synthesis. Herein, different monometallic and bimetallic catalysts supported on γ-Al2O3 nanofibers (Ni, Cu, Co, Ni-Cu, Ni-Co, Cu-Co) were prepared by the incipient wetness impregnation method and employed in the solvent-free hydrogenation of levulinic acid (LA) to GVL. The influence of metal loading, metal combination, and ratio on the activity and selectivity of the catalysts was investigated. XRD, SEM-EDS, TEM, H2-TPR, XPS, NH3-TPD, and N2 adsorption were used to examine the structure and properties of the catalysts. In this study, GVL synthesis involves the single-step dehydration of LA to an intermediate, followed by hydrogenation of the intermediate to GVL. Ni-based catalysts were found to be highly active for the reaction. [2:1] Ni-Cu/Al2O3 catalyst showed 100.0% conversion of LA with >99.0% selectivity to GVL, whereas [2:1] Ni-Co/Al2O3 yielded 100.0% conversion of LA with 83.0% selectivity to GVL. Moreover, reaction parameters such as temperature, H2 pressure, time, and catalyst loading were optimized to obtain the maximum GVL yield. The solvent-free hydrogenation process described in this study propels the future industrial production of GVL from LA.

In producing high-grade transport fuel from lignocellulosic biomass, carbon–carbon (C–C) coupling reactions are one of the most available and efficient strategies for increasing the carbon chain length and thereby producing fuel precursors.

In this work, three types of alumina‐supported bimetallic Ni−Cu catalysts [Ni−Cu/commercial non‐ordered mesoporous alumina (CMA), Ni−Cu/ordered MA (OMA), and Ni−Cu−OMA] were prepared via different fabrication strategies and investigated in the conversion of levulinic acid (LA) into γ‐valerolactone and 2‐methyltetrahydrofuran (2‐MTHF). This study employed characterization techniques and reactions to reveal the effects of the fabrication strategy on the activities of the catalysts. It was observed that the catalysts constructed on OM supports (Ni−Cu/OMA and Ni−Cu−OMA) displayed superior catalytic performance compared to those constructed on CM supports (Ni−Cu/CMA). Specifically, Ni−Cu−OMA, which was fabricated via the one‐pot evaporation‐induced self‐assembly strategy, exhibited the best catalytic performance, achieving a complete conversion of LA and a high selectivity of 73.0 % toward 2‐MTHF in a solvent‐free reaction environment. The promising activity of Ni−Cu−OMA was ascribed to the well‐dispersed active sites within the framework of the support, the enhanced metal‐support interaction, and the highly efficient exploitation of the synergistic effect between Ni and Cu. Detailed post‐characterization techniques were also employed to highlight the outstanding stability of Ni−Cu−OMA.