Nanoengineered Electrodes for Biomass-Derived 5-Hydroxymethylfurfural Electrocatalytic Oxidation to 2,5-Furandicarboxylic Acid

Over the last decades, there has been significant progress toward the development of advanced electrochemical processes in the fields of energy production and storage, surface modification of materials and environmental remediation. Within the context of biomass valorization and biorefineries, the electrochemical oxidation of 5-hydroxymethylfurfural (HMF), one of the top biomass-derived platform chemicals, to 2,5-furandicarboxylic acid (FDCA), a valuable monomer and building block of polyethylene furanoate (PEF), has emerged as a promising sustainable alternative to the chemo-catalytic synthesis paths. An additional asset of the electrochemical route is the simultaneous production of H2. The rational design of efficient nanocatalysts and nanoengineered anodes requiring lower oxidation potential is anticipated to lead to HMF electrocatalytic oxidation at even smaller applied voltage. Additionally, the utilization of heterogeneous photocatalysis combined with advantages offered by photoelectrodes capable to utilize directly the solar light, known as photoelectrochemical (PEC) catalysis, can limit the application of external voltage. This review covers all recent developments related to electrochemical oxidation of HMF to FDCA, with emphasis on the nanoengineered anodes and their structural, morphological and chemical features, as well as with regard to the associated reaction mechanisms. The potential of solar-driven photoelectrochemical oxidation methods and continuous flow electrochemical oxidation is also discussed.