Sustainable biomass upgrading coupled with H2 generation over in-situ oxidized Co3O4 electrocatalysts

Substituting overall water splitting with simultaneous biomass upgrading and H2 evolution has drawn tremendous attention due to the lower energy barrier and higher safety. Developing a cheap, efficient, and durable electrocatalyst with dual function is crucial to this novel coupling system. Herein, we propose the in-situ electrochemical tuning nonporous CoSx to hydrangea-like Co3O4 as a highly effective versatile electrocatalyst for the first time. Due to the defective structures and abundant electroactive sites, the Co3O4 catalyst achieved a complete conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) with 93.2% yield and 92.9% faradaic efficiency (FE), as well as a pure hydrogen evolution with 99.8% FE. Interestingly, it harvested a better performance with 95.8% FDCA yield for electro-oxidation of the more stable 2,5-bis(hydroxymethyl)furan (BHMF). Finally, a solar-driven integration reaction was constructed for the first time using the photovoltaic electrocatalysis (PVEC) of BHMF for the efficient and sustainable production of FDCA and H2.