Light-Induced Electron-Rich Gold Directs Nitrate Reduction to Dinitrogen

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Chemistry

Background:

• Electrocatalytic nitrate reduction reaction (NO$_{3}$RR) is a controllable method for nitrate conversion.
• Nitrate purification necessitates directing the reaction towards inert nitrogen gas (N$_{2}$) rather than soluble reactive nitrogen species.

Purpose of the Study:

• To establish operating-state electron enrichment as a design principle for selective NO$_{3}$RR towards N$_{2}$.
• To construct and investigate a Cu-induced electronically reconfigured Au (ER-Au) interface for enhanced N$_{2}$ production.

Main Methods:

• Electrochemical in situ interfacial characterization.
• Theoretical calculations.
• Product analysis and isotope-labeling experiments.

Main Results:

• The ER-Au interface achieves an electron-rich state under illumination, promoting N-N coupling of *NO intermediates.
• Selective conversion of nitrate to N$_{2}$ with 90.84% Faradaic efficiency at pH=1.
• Stable operation for 100 hours under illuminated acidic NO$_{3}$RR conditions.

Conclusions:

• Operating-state electron enrichment is a key mechanism and design principle for endpoint-selective NO$_{3}$RR.
• The ER-Au catalyst demonstrates competitive performance for N$_{2}$ production, addressing a significant challenge in nitrate reduction.
• This work provides a pathway for efficient nitrate purification through electrocatalysis.