Sustainable electrocatalytic platforms for biomass valorization: transforming 5-hydroxymethylfurfural into value-added chemicals using earth-abundant metal electrocatalysts

Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) offers an ecologically sustainable pathway for generating valuable chemicals, particularly 2,5-furandicarboxylic acid (FDCA), which represents a promising biomass-derived alternative to petroleum-based terephthalic acid in polymer manufacturing. Earth-abundant metal-based electrocatalysts have evolved into preeminent contenders for the electrocatalytic HMF oxidation reaction (HMFOR), owing to their combined advantages of cost efficiency, environmental compatibility and tunable catalytic performance. This review systematically summarizes recent breakthroughs in earth-abundant metal electrocatalysts for the HMFOR, including fundamental investigations of reaction pathways and mechanistic studies. The catalysts are classified into five major categories: (i) transition metal-based materials, (ii) metal oxides/hydroxides, (iii) transition metal interstitial compounds, (iv) metal-organic frameworks and (v) composite systems, with particular focus on advanced design strategies including heteroatom doping, defect engineering, and heterojunction fabrication. This article concludes with a critical analysis of current research frontiers, persistent challenges, and future development directions for earth-abundant metal electrocatalysts in HMFOR applications.