Electrocatalytic reduction of furfural to furfuryl alcohol using carbon nanofibers supported zinc cobalt bimetallic oxide with surface-derived zinc vacancies in alkaline medium

Electrocatalytic hydrogenation (ECH) reduction provides an environment-friendly alternative to conventional method for the upgrade of furfural to furfuryl alcohol. At present, exploring superior catalysts with high activity and selectivity, figuring out the reduction mechanism in aqueous alkaline environment are urgent. In this work, zinc cobalt bimetallic oxide (ZnMn₂O₄) with surface-derived Zn²⁺ vacancies supported by carbon nanofibers (d-ZnMn₂O₄-C) was fabricated. The d-ZnMn₂O₄-C exhibited excellent performance in electrocatalytic reduction of furfural, high furfuryl alcohol yield (49461.1 ± 228 µmol g⁻¹) and Faradaic efficiency (95.5 ± 0.5 %) was obtained. In-depth research suggested that carbon nanofiber may strongly promoted the production of adsorbed hydrogen (H_ads), and Zn²⁺ vacancies may significantly lowered the energy barrier of furfural reduction to furfuryl alcohol, the synergistic effect between carbon nanofiber and d-ZnMn₂O₄ probably facilitated the reaction between H_ads and furfuryl alcohol radical, thereby promoting the formation of furfuryl alcohol. Furthermore, the reaction mechanism was clarified by inhibitor coating and isotope experiments, the results of which revealed that the conversion of furfural to furfuryl alcohol on d-ZnMn₂O₄-C followed both ECH and direct electroreduction mechanism. © 2024 Elsevier Inc.