Cu₂O-Cu@Titanium Surface with Synergistic Performance for Nitrate-to-Ammonia Electrochemical Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Transition metals like titanium (Ti) and copper (Cu), along with their oxides (TiO2, Cu2O, CuO), are key electrocatalysts for nitrate reduction.
• Nitrate electrochemical reduction is crucial for denitrification and ammonia generation.

Purpose of the Study:

• To evaluate a composite electrode integrating Cu, Cu2O, and Ti for synergistic effects in ammonia generation.
• To investigate the influence of pH and nitrate concentration on electrode performance.
• To compare the performance of single-metal and composite electrodes.

Main Methods:

• Fabrication and electrochemical evaluation of single-metal (Ti, Cu) and composite (Cu2O-Cu/Ti) electrodes.
• Nitrate electrochemical reduction experiments under varying pH and nitrate concentrations.
• Koutecky-Levich analysis using rotating disk electrode (RDE) to determine electrochemical rate constants.

Main Results:

• The composite Cu2O-Cu/Ti electrode demonstrated significant synergistic effects for selective nitrate-to-ammonia reduction.
• Achieved a high Faradaic efficiency to ammonia of 92% and productivities of 0.28 mmolNH·cm-2·h-1 at 0.5 V vs RHE.
• Electrochemical rate constants (k) were determined: Ti (3.02 × 10-6 cm·s-1), Cu (3.88 × 10-4 cm·s-1), and Cu2O-Cu/Ti (4.77 × 10-4 cm·s-1).

Conclusions:

• The Cu2O-Cu/Ti composite electrode exhibits superior performance for selective nitrate-to-ammonia electroreduction compared to single-metal electrodes.
• The developed electrode shows promising potential for efficient ammonia generation and denitrification.
• Synergistic effects between Cu, Cu2O, and Ti enhance catalytic activity and selectivity.