Switching Urea Oxidation Reaction Pathways by Regulating Multi‐Component Sites on Chlorine‐Doped Nickel‐Cobalt Hydroxides

ABSTRACT Urea oxidation reaction (UOR) has been considered as a promising alternative to the oxygen evolution reaction for hydrogen production. So far, there are two proposed catalytic reaction alternatives for UOR, including a conventional direct six‐electron process and a rarely reported two‐stage reaction pathway. Herein, we successfully achieved the switching of UOR pathways by artificially increasing/decreasing the concentration of oxygen vacancies monotonously on nickel‐cobalt hydroxides. The “multi‐component active sites” and the UOR structural‐pathway relation were clearly elucidated by extensive experimental characterizations and density functional theory (DFT) calculations. With rich “multi‐component active sites”, chlorine‐substituted nickel‐cobalt hydroxides (NiCoClOH) exhibit a record performance for Ni 3+ ‐active sites (1.22/1.34 V versus reversible hydrogen electrode to achieve 10/100 mA cm −2 in 1 M KOH with 0.33 M urea). This work not only reported highly efficient electrocatalysts for UOR, but also paved new insights for the structure‐pathway relationship during UOR.