Synergistic O2 Activation over Asymmetric Co–Fe Dual-Atom Sites for Mild Oxidation of HMF

Abstract The oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is pivotal in biomass conversion but typically requires harsh temperatures (>100 °C) and suffers from humins formation. Herein, an asymmetrically coordinated Co–Fe dual-atom catalyst (CoFe-NC) featuring a proposed N3-Fe-N2-Co-N2 configuration is developed for efficient aerobic oxidation of HMF. Leveraging the electronegativity difference between Fe and Co, an intrasite “electron pump” drives electron transfer from Fe to Co, modulating their d-band center. This promotes superoxide radical generation while stabilizing oxygenated intermediates on Fe sites. Consequently, CoFe-NC exhibits superior catalytic performance, achieving 99.6% HMF conversion and 99.4% FDCA yield at 50 °C. This low-temperature operation effectively suppresses the thermal polymerization of HMF into humins, ensuring a high carbon balance. Remarkably, the catalyst maintains over 92% FDCA yield even at room temperature and demonstrates excellent durability over eight consecutive cycles. This work provides atomic-level insights into designing nonprecious metal catalysts for sustainable FDCA production.