S doped Cu2O-CuO nanoneedles array: Free standing oxygen evolution electrode with high efficiency and corrosion resistance for seawater splitting

Abstract

Electrochemical splitting of seawater is highly preferable over freshwater electrolysis to produce sustainable hydrogen terrifically due to its abundance in nature. Seawater electrolysis is encouraging to produce green hydrogen and safe drinking water. The accomplishment of seawater electrolysis needs robust and cost-effective anode material that should acquire an excellent catalytic activity, durability, and selectivity for OER and have high resistance against Cl- corrosion. Here we report a free-standing anode consisting of partially amorphous sulfur substituted copper oxide (S-Cu2O-CuO) nanoneedles directly grow on Cu foil. Benefiting from high electrical conductivity, plentiful active sites, high intrinsic activity per active site, and fast rate for ionic and electronic transfer, these disorders nanoneedles structured S-Cu2O-CuO demonstrate outstanding OER performance needing an overpotential of 450 mV to attain a high geometric activity (1000 mA cm−2) in 1 M KOH. Its disordered surface structure and amorphous features lead to improved corrosion resistance and durability, making it a prospective anode for direct seawater electrolysis. It requires an overpotential of 420 mV to achieve a geometric activity of 500 mA cm−2 in alkaline seawater and sustain water electrolysis for 100 h without making hypochlorite. Because of the facile, scalable, and economical approach, the catalyst is highly promising for large-scale realistic alkaline seawater electrolysis.