Pulse-Engineered Ion Redistribution Suppresses Cation Interference in Electrocatalytic Nitrate Reduction.

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic nitrate reduction (eNO3RR) to ammonia is a promising sustainable technology for wastewater treatment and nitrogen recovery.
• Real-world wastewater contains interfering ions, such as Mg2+, that inhibit eNO3RR performance.

Purpose of the Study:

• To investigate the use of pulsed electrolysis to overcome Mg2+ inhibition in eNO3RR.
• To elucidate the mechanisms by which pulsed electrolysis mitigates ion interference.

Main Methods:

• Electrocatalytic nitrate reduction experiments were conducted under static and pulsed conditions with and without Mg2+.
• Mechanistic studies involved analyzing catalyst surface changes and interfacial ion dynamics.
• Performance was evaluated based on nitrate removal efficiency and ammonia yield rate.

Main Results:

• Optimized pulsed electrolysis restored eNO3RR performance inhibited by Mg2+, achieving 98.0% nitrate removal and 3544.7 μg h-1 cm-2 ammonia yield.
• Pulsing suppressed local pH elevation, reduced Mg2+ accumulation via electric-field-induced repulsion, and enriched K+ at the interface.
• The pulsed strategy demonstrated broad applicability by mitigating cationic interference in complex wastewater analogs.

Conclusions:

• Pulsed electrolysis is an effective strategy to enhance eNO3RR in the presence of interfering ions like Mg2+.
• The study reveals the mechanistic basis of pulsed electrolysis for ion redistribution in complex water matrices.
• This work establishes a generalizable framework for improving electrocatalytic water treatment processes under realistic conditions.