Niobium oxide supported CoCu catalyst for electrooxidation of 5-hydroxymethylfurfural: Bimetallic synergy and interface engineering

Cobalt-based catalysts have demonstrated significant potential for the selective electrooxidation of biomass-derived 5-hydroxymethylfurfural (5-HMF) into high-value 2,5-furandicarboxylic acid (FDCA). However, monometallic systems suffer from sluggish redox kinetics of cobalt species and insufficient reactant adsorption. In this study, we address these limitations by constructing a niobium oxide-supported cobalt‑copper bimetallic catalyst (CoCu/Nb₂O₅), leveraging bimetallic synergy and interface engineering to enhance catalytic activity. The incorporation of copper species facilitates efficient electron transfer between cobalt species of different valence states, while the Nb₂O₅ support strengthens electronic interactions with 5-HMF molecules and enables lattice oxygen participation in the reaction. Furthermore, the porous structure of the support improves bimetallic dispersion and provides enhanced mass transport pathways. The optimized CoCu/Nb₂O₅ catalyst achieves complete 5-HMF conversion and a remarkable 98.3 % FDCA yield at 1.4 V vs RHE, alongside excellent stability and reusability. Additionally, the catalyst demonstrates versatility by efficiently converting furfural into furoic acid, another biomass-derived platform molecule. This work offers valuable insights for designing advanced cobalt-based electrocatalysts and promotes the valorization of biomass resources.