Single-atom Tungsten Doping Induced Chemical-electrochemical Coupled Pathway on Ni(OH)2 Enables Efficient Urea Electrooxidation

Abstract

Electrocatalytic urea oxidation reaction (UOR) has emerged as a promising alternative to oxygen evolution reaction (OER) for wastewater recycling and energy recovery. However, traditional UOR pathway on NiOOH surface faces is hindered by the rate-limiting desorption of *COO and the competition between UOR and OER. In this study, we propose a chemical-electrochemical coupled pathway for direct UOR, achieved through the construction of single-atom W-doped nanoporous P-Ni(OH)₂ catalyst (np/W-P-Ni(OH)₂). Specifically, np/W-P-Ni(OH)₂ catalyst exhibits exceptional UOR performance with an ultralow potential of 1.28 V vs. RHE to reach 10 mA cm^-2 and a high UOR selectivity exceeding 90% across the entire potential range. A collection of in-situ spectroscopies and theoretical calculations reveal that single-atom W dopant not only accelerates the formation of Ni(OH)O active intermediates by modulating the O charge in the lattice hydroxyl, but also lowers the energy barrier of the proton-coupled electron transfer step and the cleavage of C−N bond, thus realizing the highly-efficient UOR.