Defect-Engineered La-Mn Co-Doped β-PbO₂ Anodes for Energy-Efficient Zinc Electrowinning

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• High energy consumption in zinc production is linked to inefficient lead anodes and slow oxygen evolution reaction (OER).
• Developing advanced anode materials is crucial for improving energy efficiency in electrochemical processes.

Purpose of the Study:

• To engineer a novel La-Mn co-doped β-PbO₂ anode to enhance the oxygen evolution reaction (OER) kinetics.
• To reduce the high energy consumption associated with lead anodes in industrial zinc production.

Main Methods:

• Fabrication of La-Mn co-doped β-PbO₂ anodes via electrodeposition.
• Characterization using X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS).
• Electrochemical performance evaluation using Electrochemical Impedance Spectroscopy (EIS) and polarization measurements.

Main Results:

• La doping induced lattice shrinkage and altered electron structure, facilitating Mn⁴⁺ to Mn³⁺ conversion and increasing surface active oxygen sites.
• Electrochemical Impedance Spectroscopy (EIS) revealed a 4.2-fold decrease in charge transfer resistance (R_ct) and a significant increase in electrochemically active surface area (ECSA).
• The La-Mn-β-PbO₂ anode exhibited a low overpotential (840 mV) and Tafel slope (265 mV dec^-1) at industrial current density (50 mA cm^-2).

Conclusions:

• The La-Mn co-doped β-PbO₂ anode demonstrates significantly improved catalytic activity for OER, reducing energy consumption by 187.10 kWh/ton of zinc.
• This developed anode represents a promising, energy-saving alternative for industrial zinc production, addressing limitations of traditional lead anodes.