Radical relay‐driven HMF oxidation enabled by single‐atom Co‐N‐C catalysts at low temperature and ambient pressure

Abstract The 5‐hydroxymethylfurfural (HMF) oxidation to 2,5‐furandicarboxylic acid (FDCA) is a pivotal reaction in biomass refinery; however, it is challenged by harsh reaction conditions and suboptimal reaction kinetics. In this study, we propose a “radical relay by single‐site catalysis” strategy to achieve HMF oxidation at low temperatures (80°C) and atmospheric oxygen conditions. Experimental results demonstrated that employing a Co‐N‐C catalyst, with CoN 3 as the primary active site and TBHP as radical initiator, enabled a 95% FDCA yield and corresponding productivity of 29.9 mmol·g metal −1 h −1 , which was 2.1 times higher than that observed without the initiator. Mechanistic investigations revealed that the isolated CoN 3 with TBHP effectively lowered the activation energy barrier for the molecular oxygen, facilitating the generation of superoxide radicals, thereby boosting HMF oxidation without high pressure O 2 . Furthermore, this strategy exhibited good versatility to various aldehydes, thus presenting a mild and environmentally friendly catalytic system for HMF oxidation.