Revealing the promoting effect of heterojunction on NiS/MoO in urea oxidation assisted water electrolysis.

Investigating efficient non-precious metal-based catalysts for water electrolysis to produce hydrogen is a significant and urgent need in the field of clean energy technologies. Moreover, utilizing transition metal dichalcogenides (TMDs) to replace the oxygen evolution reaction (OER) with the urea oxidation reaction (UOR), coupled with the hydrogen evolution reaction (HER), is an effective energy-saving hydrogen production method. A heterostructure NiS/MoO catalyst was prepared by a simple method, which exhibits excellent activity for UOR, requiring only 1.4 V to reach 100 mA cm. The high performance is attributed to the presence of the heterostructure, which effectively promotes charge redistribution and optimizes the electronic structure of the catalyst, thereby enhancing its adsorption capacity for intermediates. As a result, an electrolyzer assembled with NiS/MoO as a bifunctional catalyst demonstrates excellent catalytic activity, ensures stability for over 200 h at a current density of 10 mA cm, and achieves a hydrogen production rate of 0.402 mmol h at a potential of 1.8 V.