(532av) Mechanistic Study of Efficient Urea Oxidation Reaction on Ni-Layered Double Hydroxides Under Alkaline Medium

Urea is a dominant source of nitrogen in domestic waste water, in which causes eutrophication of surface waters. Compared to its importance of environmental concerns, a process to effectively treat urea has not been clearly developed. Urea oxidation reaction (UOR) is a prospective technology for simultaneous H₂ generation and nitrogen suppression in the process of water being used for energy production. UOR can replace the sluggish oxygen evolution reaction (OER) with the thermodynamically favorable UOR, alleviating the issue of urea-rich water contamination. Currently, Ni-related layered double hydroxides (LDHs) are the most active electrocatalyst not only for the alkaline oxygen OER but also for the UOR. Recent studies have only focused on UOR under neutral pH system, neglecting the cationic effect. Herein, DFT calculations reveal UOR mechanism on K⁺ ion intercalated γ-NiOOH (01-10) under the alkaline condition. Moreover, contrary to previously reported DFT results under neutral pH system with having *NH₂ adsorption conformation of urea on LDHs, CO* adsorption conformation of urea was found in this study. These findings will provide insights into both waste water treatment and water energy systems.