In Situ Construction of a Mn2+-Doped Ni3S2 Electrode with Highly Enhanced Urea Oxidation Reaction Performance

Abstract

Urea, as a prospective energy source, is rarely utilized for lack of effective catalysts to overcome its sluggish kinetics during its electrolysis. Exploiting low-cost and high-efficiency catalysts to accelerate the urea oxidation reaction (UOR) does make sense as it can relieve not only energy shortage but also the water contamination problems. In this work, the Ni₃S₂ nanosheets grown on the Ni foam with different amounts of Mn²⁺ doping were developed as useful electrocatalysts toward UOR. The experimental and computational methods were performed to explore the properties of obtained samples. We found that the doping of Mn²⁺ could distinctly regulate the charge distribution of Ni₃S₂ by which the performance was observably optimized. We also compared the behaviors of obtained catalysts with various dopant concentrations of Mn²⁺. Especially, Ni₃S₂ grown on the Ni foam with the addition of 0.2 mmol of Mn²⁺ exhibits splendid properties with a lower potential and superior longevity, which can achieve a current density of 100 mA cm–² at a voltage of only 1.397 V (vs reversible hydrogen electrode) in 1.0 M KOH containing 0.5 M urea solution, indicating that our findings can serve as promising electrocatalysts for urea electrolysis.