Sulfur‐Vacancy Engineering Accelerates Rapid Surface Reconstruction in Ni‐Co Bimetal Sulfide Nanosheet for Urea Oxidation Electrocatalysis

Abstract Developing a highly efficient catalyst for electrocatalytic urea oxidation reaction (UOR) is not only beneficial for the degradation of urea pollutants in wastewater but also provides a benign route for hydrogen production. Herein, a sulfur‐vacancy (S v ) engineering is proposed to accelerate the formation of metal (oxy)hydroxide on the surface of Ni‐Co bimetal sulfide nanosheet arrays on nickel foam (S v ‐CoNiS@NF) for boosting the urea oxidation electrocatalysis. As a result, the obtained S v ‐CoNiS@NF demonstrates an outstanding electrocatalytic UOR performance, which requires a low potential of only 1.397 V versus the reversible hydrogen electrode to achieve the current density of 100 mA cm −2 . The ex situ Raman spectra and density functional theory calculations reveal the key roles of the S v site and Co 9 S 8 in promoting the electrocatalytic UOR performance. This work provides a new strategy for accelerating the transformation of electrocatalysts to active metallic (oxy)hydroxide for urea electrolysis via engineering the surface vacancies.