Hierarchical copper oxide@nickel-cobalt layered double hydroxide for efficient 5-hydroxymethylfurfural electro-oxidation in alkaline seawater

Developing efficient electrocatalysts for biomass electro-oxidation in alkaline seawater is of great significance but remains less explored. Herein, we reported a hierarchical structure consisting of nickel-cobalt layered double hydroxide nanosheets and copper oxide nanowires (CuO@NiCo-LDH), which was favorable for increasing active sites and facilitating electron transfer during 5-hydroxymethylfurfural oxidation (HMFOR). As-designed CuO@NiCo-LDH catalyst achieved a high yield of 2,5-furandicarboxylic acid (FDCA, 89%) and 82% faradaic efficiency (F.E.). It also showed a large current density of 133.4 mA cm −2 at 1.4 V vs. RHE, outperforming most of the previously reported Ni/Co-based HMFOR electrocatalysts. More importantly, it also showed an outstanding HMFOR performance in alkaline seawater, suggesting great promise in practical electrolysis.