Ni-Doped MnO₂ Nanosheet Arrays for Efficient Urea Oxidation

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Urea oxidation reaction (UOR) is a promising alternative to oxygen evolution reaction for energy-efficient electrolysis.
• Developing efficient electrocatalysts is crucial to overcome the sluggish kinetics of UOR.
• Existing Ni-based catalysts often require high overpotentials due to self-oxidation to NiOOH.

Purpose of the Study:

• To develop a novel electrocatalyst for efficient urea oxidation reaction (UOR).
• To investigate the UOR performance of Ni-doped MnO2 nanosheet arrays.
• To understand the role of Ni doping and nanostructure in enhancing UOR activity.

Main Methods:

• Synthesis of Ni-doped MnO2 (Ni-MnO2) nanosheet arrays on nickel foam.
• Electrochemical characterization of Ni-MnO2 for UOR.
• Analysis of the catalytic mechanism and active sites.

Main Results:

• Ni-MnO2 nanosheet arrays exhibited distinct UOR behavior, proceeding before NiOOH formation.
• Achieved a high current density of 100 mA cm-2 at a low potential of 1.388 V vs RHE.
• Ni doping modified the electronic structure of Mn, increasing Mn3+ species and enhancing UOR activity.

Conclusions:

• Ni-doped MnO2 nanosheet arrays are highly efficient electrocatalysts for UOR.
• The nanostructure and Ni doping are key factors for the enhanced catalytic performance.
• This catalyst offers a pathway for reduced energy consumption in electrolysis systems.