Electrooxidation of 5-hydroxymethylfurfural and electroreduction of nitrobenzene by hollow CoFeP cubes/rGO/Ni foam

Abstract

Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylate (FDCA) has attracted great attention due to its potential for producing degradable plastics. But, HMF electrooxidation still faces challenges such as high overpotentials and sluggish kinetics. Meanwhile, H₂ evolution at the cathode is less cost-effective than cathodic reactions producing valuable chemicals. In view of this, a MOF-derived CoFeP cube anchored on rGO-encapsulated nickel foam (NF) via a facile wet-chemical method is reported. The CoFeP–rGO catalyst delivers a low potential of 1.38 V at a current density of 100 mA cm⁻² in 1 M KOH containing 10 mM HMF, achieving ∼100% conversion, a 96% yield of FDCA, and 100% Faraday efficiency (FE). It acts as a bifunctional catalyst, demonstrating electrocatalytic reduction of nitrobenzene (NB) at low overpotential with 91% conversion. In the proposed mechanism, the CoFeP–rGO interface is proved to play a crucial role in increasing the catalytic activity via promoting dispersion of the CoFeP nanocrystals on the substrate and accelerating the electron transfer rate across the interface.