Highly amorphized nickel-based ternary metal catalysts for efficient urea oxidation reaction

Developing efficient catalysts for the urea oxidation reaction (UOR) is of critical importance in advancing sustainable energy. The transient loss of high-valence Ni active sites is one of the key factors limiting the reaction kinetics of UOR. To addressing this challenge, we successfully synthesize transition metal M (M = Mn, Co, Fe)-doped NiMoO₄ amorphized self-supported electrodes (NiMoO₄/M) through a two-step hydrothermal method. The NiMoO₄/Mn shows superior stability and selectivity, achieving a current density of 100 mA cm^-2 at an overpotential of 1.48 V (vs. RHE). The results reveal that the catalytic activity improvement stems from amorphized surface structure and the synergistic effects among Ni-Mo-M. During electrochemical reconstruction, ternary Ni-Mo-M active sites are formed, with Mo acting as an electron acceptor to regulate the electronic configuration of Ni. The doped metals further enhance the electron-accepting ability of Mo, facilitating electron transfer between Ni and Mo, optimizing the hydroxide-coupled electron transfer process, thereby accelerating UOR kinetics and advancing the process's efficiency. This study offers a strategic framework for designing highly efficient multi-metallic UOR catalysts through precise modulation of electronic and structural properties.