Efficient Electrocatalytic Oxidation of 5-Hydroxymethylfurfural Coupled with 4-Nitrophenol Hydrogenation in a Water System

Electrocatalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) to value-added 2,5-furandicarboxylic acid (FDCA) is of great significance for sustainable chemical production. The key challenge is to establish an electrocatalytic system with a wide potential window, which can selectively oxidize HMF to FDCA without causing water oxidation. In this study, Cu foam decorated with Cu(OH)2 (CF-Cu(OH)2) was successfully fabricated as an efficient catalyst, and CuOOH active species generated by electrochemistry were demonstrated as the main catalytic sites for HMF oxidation. As a result, the current density of CF-Cu(OH)2 reached up to 198.2 mA/cm2 (100 mM HMF, 1.0 M KOH, 0.8 V vs Ag/AgCl), and a high faradic efficiency close to 100% for FDCA production (yield: 98.7%) was realized. Moreover, we reveal the mechanism for the electro-oxidation of HMF to FDCA and further provide an insight into the oxidation pathway for HMF. A paired electrochemical system exhibits superior catalytic performance of synergetic reactions (HMF oxidation and 4-NP reduction). Therefore, this work proposes a strategy to simultaneously produce two types of value-added chemicals at both electrodes, which can be applied in other electrocatalytic systems for the green synthesis of organic compounds.