Degradation Effect on Oxidation of 5-Hydroxymethyl-2-furaldehyde over Cobalt-Iron Electrocatalysts in Alkaline Condition

Nowadays, the excessive utilization of fossil-based chemicals has caused serious environmental problems, especially due to the negative carbon footprints. Addressing this issue by substituting fossil resources with environmentally friendly biomass is imperative. This study focuses on the electrooxidation of 5-hydroxymethyl-2-furaldehyde (HMF), a biomass-derived chemical, into 2,5-furandicarboxylic acid (FDCA) in alkaline solutions, a crucial feedstock, for the chemical industry. Given the acknowledged instability of HMF in an alkaline environment, this research investigated the kinetic approximation of HMF degradation under varying concentrations of KOH solutions (0.1M and 1M KOH) over 12hours. Then, the electrooxidation of HMF to FDCA over cobalt-iron-based catalysts was investigated. As a result, the FDCA was successfully produced in 0.1M KOH solution with a remarkable yield of up to 94%, while a higher concentration (1M KOH solution) accelerated the electrooxidation process. However, the yield and Faradaic efficiency could be greatly dropped after 12hours of storing time due to the effects of HMF degradation reactions (Cannizaro and polymerization reactions). Therefore, this degradation phenomenon should be considered on an industrial scale, particularly when HMF may be stored for an extended period before utilization.