The depletion of fossil fuel reserves and the urgent demand for low-carbon energy systems make the upgrading of biomass-derived aqueous ethanol to higher alcohols a highly attractive route toward advanced liquid fuels. However, simultaneously achieving high conversion, high selectivity, and controllable carbon-number distribution remains a significant challenge. In this study, Mo-doped NiMo/CS and NiMo@C-MgO catalysts were constructed and their catalytic performance for the conversion of aqueous ethanol was systematically investigated. For the NiMo/CS catalyst prepared by wet impregnation, carbonization at 500℃ followed by reaction at 230℃ affords an ethanol conversion of 48.39% with 95.1% selectivity to C4 + alcohols, among which C8–C16 higher alcohols account for 20.53% selectivity. Furthermore, a core–shell NiMo@C-MgO catalyst was fabricated via a sol–gel route. Benefitting from the confinement effect of the carbon shell and the cooperative action of basic MgO sites and NiMo active centers, the interfacial electronic structure was effectively tuned, overcoming the intrinsic bulk electronegativity of the metal elements and giving rise to electron-rich Ni active sites (Niδ⁻). As a result, NiMo@C-MgO-500 achieved 70.1% ethanol conversion and 94.5% C4 + alcohol selectivity, with the selectivity of C8–C16 higher alcohols reaching 48.8%, while maintaining good stability after four consecutive cycles. This study provides high-performance NiMo-based catalysts and mechanistic insight for the efficient conversion of bioethanol into higher alcohols, and highlights the potential of this catalytic route for the production of advanced, biomass-derived liquid fuels with tunable molecular structures. • NiMo/CS and NiMo@C–MgO catalysts upgrade aqueous ethanol to higher alcohols. • NiMo/CS gives 48.39% ethanol conversion with 95.1% selectivity to C4⁺ alcohols. • NiMo@C–MgO achieves 70.1% conversion and 48.8% selectivity to C8–C16 alcohols. • Carbon shell, MgO basic sites and Ni–Mo synergy co-tune amphiphilicity and C–C coupling. • DFT shows Mo→Ni electron transfer forming Niδ⁻ sites that lower the rate-determining barrier.
Wang et al. (Tue,) studied this question.