Amorphous nickel sulfoselenide for efficient electrochemical urea-assisted hydrogen production in alkaline media

Amorphous Ni sulfoselenide on the surface of Ni(OH)2 nanoplate that is supported by nickel foam is synthesized, which demonstrates high activity and durability for hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) in alkaline media. As for HER, the introduction of sulfur in Ni sulfoselenide not only increases the electrochemical active area, but also improves the water adsorption ability and provides an optimal adsorption site for hydrogen atom. As for UOR, the in-situ formed amorphous oxyhydroxide is believed as the real active species. The electrolyzer assembled by Ni sulfoselenide electrodes shows a low voltage of 1.47 at 10 mA cm−2 in 1 M KOH + 0.5 M urea, which is much lower than that required for overall water splitting. The present work demonstrates an effective bifunctional electrode for HER and UOR that can be used to produce hydrogen and remove pollutant (urea) in water at the same time.