Superhydrophilic NiSe ₂ /NiCr‐Layered Double Hydroxide Nanocomposite for Efficient Urea Electrooxidation and Hydrogen Production Efficiency via Water‐Urea Electrolysis

Abstract Selenized nickel chromium layered double hydroxide, referred to as NiSe ₂ /NiCr‐LDH is presented here as an efficient and sustainable electrocatalyst for urea‐assisted water electrolysis. Compared to pristine NiCr‐LDH, hydrothermally synthesized and thoroughly characterized (structural, morphological, textural and compositional properties) batch of NiSe ₂ /NiCr‐LDH reveals significant improvement in the electrocatalytic activity toward urea oxidation reaction (UOR, E ₁₀ = 1.351 V and Tafel slope = 31 mV dec ⁻¹ ), and hydrogen evolution reaction (HER, E ₁₀ = 0.117 V, Tafel slope = 72 mV dec ⁻¹ ). The improved UOR and HER activities are attributed to selenization and Cr‐doping in Ni‐based LDH structure. It is corroborated by higher electrochemically active surface area (ECSA), electrical conductivity and mass transport, favorable adsorption and desorption of reaction intermediates, and enhanced wettability of the catalyst. The real‐time application of NiSe ₂ /NiCr‐LDH as a bifunctional UOR and HER catalyst is demonstrated by achieving a cell potential corresponding to E ₁₀ = 1.42 V for the alkaline water‐urea electrolysis. The overall energy consumption for hydrogen generation via water‐urea electrolysis is decreased by ≈16% as compared to that of water electrolysis, with 95% faradaic efficiency. This work highlights that selenization of Ni and Cr‐based LDH is a promising approach for designing a sustainable hydrogen‐generating water‐urea electrolyzer.