Highly selective electrochemical nitrate reduction using copper phosphide self-supported copper foam electrode:...

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Engineering

Background:

• Electrochemical denitrification requires highly active and selective electrodes.
• Existing copper-based electrodes face challenges in activity and selectivity for nitrate reduction.
• Developing advanced electrode materials is crucial for efficient wastewater treatment.

Purpose of the Study:

• To develop a novel binder-free composite electrode for enhanced electrochemical nitrate reduction.
• To investigate the catalytic mechanism and stability of the new electrode.
• To design a multi-stage treatment strategy for comprehensive wastewater remediation.

Main Methods:

• Fabrication of a composite electrode (Cu3P/CF) by direct growth of copper phosphide on copper foam.
• Electrochemical evaluation using cyclic voltammetry (CV) and electrochemical impedance spectra (EIS).
• Testing the electrode's performance under specific nitrate and chloride concentrations.
• Design and implementation of a two-stage wastewater treatment process.

Main Results:

• The Cu3P/CF electrode demonstrated high electrochemical performance for nitrate reduction (84.3%) with excellent N2 selectivity (98.01%).
• Mechanism involves electron transfer facilitated by Cu3P as a bifunctional catalyst and mediator.
• The electrode maintained catalytic activity over eight cycles, indicating good stability.
• A two-stage treatment strategy effectively removed chemical oxygen demand (COD) and total nitrogen (TN) from real wastewater.

Conclusions:

• The binder-free Cu3P/CF composite electrode offers superior activity and selectivity for electrochemical nitrate reduction.
• Cu3P acts as a bifunctional catalyst and electron mediator, enhancing the denitrification process.
• The developed two-stage treatment strategy shows potential for treating real wastewater, addressing both COD and TN.