Low‐Grade Water as a Promising Candidate for Green Hydrogen Generation

Abstract In this study, low‐grade water as an alternative to pure water for generating green hydrogen is studied using non‐precious hafnium nickel diselenide/reduced graphene oxide (HfNiSe 2 /rGO) electrocatalyst. The model electrocatalyst has performed well for hydrogen and oxygen generation. To attain 10 mA cm −2 of current density, it requires only 1.56, 1.58, and 1.61 V for deionized water (DI), tertiary effluent (TE), and raw wastewater (RWW), respectively, with high durability. In addition to generating green energy, pollutants are successfully removed during electrolysis. The synthesized hafnium‐based electrocatalyst is active toward urea electrolysis, requiring only 1.46 V for 10 mA cm −2 with high stability. Replacing high‐purity water with low‐grade water opens a new opportunity window for establishing a sustainable hydrogen economy and water management strategies.