Cobalt-based catalysts for catalytic oxidation of biomass-derived 5-Hydromethylfurfural to value-added chemicals

The catalytic conversion of bio-derived 5-Hydroxymethylfurfural (HMF) into useful chemical building blocks, particularly to 2,5-furandicarboxylic acid (FDCA) is a crucial process for biomass utilization. Although recent decade has witnessed significant improvement of chemo-catalytic and electro-catalytic oxidation of HMF technologies, there are several technological challenges hindering further progress, such as not well-defined active sites, poorly defined surface, uncontrollable side reactions and harsh reaction conditions. To overcome these limitations, improvements can be made through catalyst particles engineering, electronic configuration regulation over the particles, active species modification, and mechanism clarification. This comprehensive review focuses on synthesis strategies, morphologies and mechanistic investigation of Co-based catalysts for both chemo-catalytic and electro-catalytic HMF oxidation to FDCA. The relationship between catalysts structures, active species, Co valence state, catalytic activity, and selectivity for –CHO and –OH group oxidation, is extensively discussed, providing valuable insights for the future design of atom-efficient biomass conversion to fuels and chemicals. It is found that morphologies, metal-metal/metal-support synergistic interactions, acidic/basic properties and valence state of metals are crucial for selective C–H and O–H activation during HMF oxidation. For further development of HMF oxidation, it is crucial to explore environmentally friendly reaction media, conduct comprehensive studies on the intrinsic kinetics of HMF oxidation, employ advanced characterization techniques and theoretical calculations to uncover the fundamental reactive mechanisms, and investigate the system under industrial required conditions.