Synergistic modulation of the electronic structure and morphology in porous Mo-NiFe LDH for enhanced electrocatalytic UOR

Abstract

The urea oxidation reaction (UOR), as a key process in renewable energy technologies and wastewater treatment, suffers from sluggish reaction kinetics due to its six-electron transfer characteristics, necessitating the development of highly efficient catalysts. In this work, a one-pot method combined with a sodium borohydride (NaBH₄) etching strategy was employed to successfully prepare porous Mo-doped NiFe-layered double hydroxide (P-Mo-NiFe-LDH), achieving a significant enhancement in UOR performance. Studies revealed that Mo doping altered the microscopic morphology of NiFe-LDH and promoted the transition of Ni²⁺/Fe²⁺ to higher valence states (Ni³⁺/Fe³⁺), thereby improving the reaction kinetics. Meanwhile, the porous structure constructed by NaBH₄ etching not only exposed abundant active sites but also optimized the electron transport pathways. This synergistic effect of morphology regulation and electronic structure optimization enabled P-Mo-NiFe-LDH to exhibit outstanding catalytic performance in a 1 M KOH + 0.33 M urea electrolyte: a current density of 10 mA cm⁻² was achieved at just 1.39 V (vs. RHE), with a Tafel slope of 38.7 mV dec⁻¹, demonstrating a clear advantage over most reported NiFe-based catalysts. This catalytic potential is 90 mV lower than that of the water oxidation reaction, offering certain energy-saving benefits. The synergistic strategy of porous structures and heteroatom doping in this work provides new insights for designing high-performance LDH-based electrocatalysts.