Multifunctional iron–cobalt heterostructure (FeCoHS) electrocatalysts: accelerating sustainable hydrogen generation through efficient water electrolysis and urea oxidation

The urgent need to address escalating environmental pollution and energy management challenges has underscored the importance of developing efficient, cost-effective, and multifunctional electrocatalysts. To address these issues, we developed an eco-friendly, cost-effective, and multifunctional electrocatalyst <i>via</i> a solvothermal synthesis approach. Due to the merits of the ideal synthesis procedure, the FeCoHS@NF electrocatalyst exhibited multifunctional activities, like OER, HER, OWS, UOR, OUS, and overall alkaline seawater splitting, with required potentials of 1.48, 0.130, 1.59, 1.23, 1.40, and 1.54 V @ 10 mA cm^-2, respectively. Moreover, electrolysers required only 1.40 V at 10 mA cm^-2 for energy-saving urea-assisted hydrogen production, which was 190 mV lower than that of the alkaline water electrolyser. The alkaline sewage and seawater purification setup combined with the FeCoHS@NF electrolyzer led to a novel approach of producing pure green hydrogen and water. The ultrastability of the FeCoHS@NF electrocatalyst for industrial applications was confirmed using chronopotentiometry at 10 and 100 mA cm^-2 over 110 h for OER, HER, UOR, and overall water splitting. The production of hydrogen using the FeCoHS@NF electrocatalyst in alkaline sewage water and seawater offers multiple benefits, including generation of renewable hydrogen energy, purification of wastewater, reduction of environmental pollutants, and low cost and low electricity consumption of the electrolyser system.