Investigation on the Electrocatalytic Oxidation of 5-Hydroxymethylfurfural in a Flow Electrolytic Cell Using Ni(OH) ₂ /NF

5-Hydroxymethylfurfural (HMF) can be efficiently converted into valuable chemicals, such as 2,5-furandicarboxylic acid (FDCA), through controlled electrocatalytic processes. Electrocatalytic synthesis in flow electrolytic cells has become particularly promising for industrial-scale applications. This study developed a self-supported Ni(OH)2/NF catalyst fabricated on nickel foam via an acid-etching approach for continuous-flow HMF oxidation. Optimal performance was achieved at an electrolyte flow rate of 160 mL min–1, an applied potential of 1.65 V (vs RHE), a HMF concentration of 10 mmol L–1, and a temperature of 25 °C. The catalyst exhibited robust activity, achieving 70% HMF conversion with 40% FDCA yield per cycle. Over four consecutive 40 h cycles, the system produced a total of 0.51 g of FDCA, demonstrating the viability of electrocatalytic approaches for sustainable biomass conversion.