Seawater-corrosion-engineered CoNi electrode for highly efficient oxidation of 5-(Hydroxymethyl)furfural

The green synthesis of 2,5-furandicarboxylic acid (FDCA), famous as a bio-based polymer monomer from the 5-hydroxymethylfurfural (HMF), offers a promising route to reduce the usage of petroleum-based polymer polyethylene terephthalate. Although the electrocatalytic preparation of FDCA rids high temperature and pressure limits, most electrocatalysts used in the HMF oxidation reaction (HMFOR) are usually fabricated in harsh conditions. Therefore, we propose a method to improve the performance of electrocatalysts in the HMFOR reaction by introducing metal salts using natural seawater as the main feedstock. The final Co-sw/NF realized a 97.4% FDCA yield and 97.3% Faraday efficiency (FE). In-situ Raman techniques identified the catalytically active species of the catalysts employed in the HMFOR process. The effect of metal salts on catalyst energy levels is discussed in detail using the ultraviolet photoelectron spectroscopy (UPS) and Tauc plot method. The adsorption performance of HMF on the catalyst was determined by calculating the d-band centers and applying open circuit potential (OCP) tests. Furthermore, we elucidate the specific mechanism in terms of electron transport pathways.