Key Roles of Interfacial OH⁻ ion Distribution on Proton Coupled Electron Transfer Kinetics Toward Urea Oxidation Reaction

Enhancing alkaline urea oxidation reaction (UOR) activity is essential to upgrade renewable electrolysis systems. As a core step of UOR, proton-coupled electron transfer (PCET) determines the overall performance, and accelerating its kinetic remains a challenge. In this work, a newly raised electrocatalyst of NiCoMoCuOxHy with derived multi-metal co-doping (oxy)hydroxide species during electrochemical oxidation states is reported, which ensures considerable alkaline UOR activity (10/500 mA cm−2 at 1.32/1.52 V vs RHE, respectively). Impressively, comprehensive studies elucidate the correlation between the electrode-electrolyte interfacial microenvironment and the electrocatalytic urea oxidation behavior. Specifically, NiCoMoCuOxHy featured with dendritic nanostructure creates a strengthened electric field distribution. This structural factor prompts the local OH− enrichment in electrical double layer (EDL), so that the dehydrogenative oxidation of the catalyst is directly reinforced to facilitate the subsequent PCET kinetics of nucleophilic urea, resulting in high UOR performance. In practical utilization, NiCoMoCuOxHy-driven UOR coupled cathodic hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO2RR), and harvested high value-added products of H2 and C2H4, respectively. This work clarifies a novel mechanism to improve electrocatalytic UOR performance through structure-induced interfacial microenvironment modulation.