Sulfur induced surface reconfiguration of Ni₁Cu₃-S-T/CP anode for high-efficiency ammonia electro-oxidation

As an effective method of removing ammonia from wastewater, ammonia electro-oxidation technology has emerged as an attention treatment owing to its simple operation and better tolerance to toxic pollutants. Notably, how to solve the sluggish kinetics of ammonia oxidation reaction (AOR) is the key to the technology. In this work, a high-efficiency catalytic electrode was obtained by deepening the surface electrochemical reconfiguration of NiCu nanoparticles through sulfur-doping. Electrochemical test showed that the Ni₁Cu₃-S-T/CP electrode had a maximum current density of 150 mA/cm² at 1.69 V vs RHE. Density functional theory calculations further elucidated that the proper introduction of copper optimized the electron band structure and ameliorated ammonia adsorption and desorption capacity, forcing the early start of AOR at low potential. Consequently, after 5 h electrolysis at 1.50 V, the removal efficiency of NH₄⁺-N was 96.23 %. As well as the electrode maintained good stability in 12 cycles tests.