Microwave-Activated Peroxyl Radicals Accelerate Hydroxymethyl Oxidation on the AuPd/C Catalyst for Mild Synthesis of FDCA

Abstract

2,5-Furandicarboxylic acid (FDCA), an important platform chemical, is often synthesized from hydroxymethylfurfural (HMF), while the energy efficiency of the reaction is limited by the slow hydroxymethyl oxidation, resulting in poor technoeconomy. In this study, a bimetallic Au–Pd microwave-responsive catalyst was designed to achieve high-efficiency synthesis of FDCA by coupling microwave-activated peroxyl radical formation from hydrogen peroxide (H₂O₂). Pd sites were responsible for dissociating H₂O₂ into peroxyl radicals (·OOH), and Au sites accepted peroxyl radicals and oxidized HMF into FDCA. The microwave-boosted reaction synergy on the bimetallic Au–Pd dual active centers enabled the reaction to occur at near-room temperature (45 °C) and reached the highest FDCA yield of 88 mol % at 65 °C. Experimental and electric-field DFT studies revealed that microwaves increased the rate constant of H₂O₂ decomposition by 1.6-fold compared to conventional heating methods, with an ultrahigh H₂O₂ utilization rate of 90%. This work provides a new platform for highly efficient peroxyl radical formation with microwave energy, which can be extended to a wider range of oxidation reactions with accelerated reaction kinetics and enhanced energy efficiency.