Turning damages into benefits: Corrosion-engineered cobalt foam for highly efficient biomass upgrading coupled with H2 generation

Electrocatalysis using 5-hydroxylmethylfurfural (HMF) as a substrate to produce 2,5-furandicarboxylic (FDCA) is a potentially sustainable and mild route to harvest both value-added chemicals and clean energy hydrogen. However, the poor chemical and thermal stability of HMF has impeded its storage and industrialization. Additionally, the uncontrollability, scalability, and cost of catalyst preparation methods are rarely considered in this field. Herein, we capitalize on the spontaneous and harmful corrosion phenomenon occurring under natural conditions to prepare efficient Co-based catalysts for the electrooxidation 2,5-bis(hydroxymethyl)furan (BHMF) with more stable dihydroxy groups, coupled with hydrogen evolution. The preparation of electrocatalysts through corrosion engineering is a straightforward, cost-effective, highly feasible, and scalable approach, requiring minimal equipment. In the optimal concentration of 200 mM BHMF, an ultrahigh current density of 1981.7 mA cm−2 was achieved at 2.293 V vs. RHE, contributed by both BHMF oxidation and oxygen evolution reaction (OER). Chronoamperometric electrolysis realized efficient FDCA production with 95.4% yield and 96.5% faradaic efficiency (FE) at an ultralow potential of 1.4 V vs. RHE. Since it is etched and grown on the substrate itself, the catalyst prepared by corrosion engineering is very stable and undergoes ten successive chronoamperometric electrolysis without significant structural or performance failure. Moreover, kinetic analyses are investigated to explore the origin of catalytic activity and reaction energy barrier. Finally, to further realize the potential of FDCA and H2 production in practical application, we innovatively designed a device with a two-electrode electrolyzer and a solar cell in series to drive BHMF electrooxidation with outdoor sunlight. The complete conversion of BHMF only takes 90 min, achieving a 93.5% FDCA yield and nearly theoretical hydrogen evolution.