Elucidation of Pathways for NO Electroreduction on Pt(111) from First Principles

Area of Science:

• Electrochemistry
• Surface Science
• Computational Chemistry

Background:

• Understanding nitric oxide electroreduction is crucial for catalysis.
• The exact mechanisms for ammonia and nitrous oxide formation remain unclear.

Purpose of the Study:

• To elucidate the electroreduction mechanism of nitric oxide on Pt(111).
• To investigate the roles of electrochemical steps and the aqueous environment.

Main Methods:

• First principles calculations
• Electrokinetic rate theories
• Explicit water models
• Butler-Volmer kinetics

Main Results:

• High N-O bond cleavage barriers indicate indirect pathways.
• Ammonia is formed via water-assisted protonation and dissociation at <0.3 V.
• Nitrous oxide forms via an Eley-Rideal mechanism, not Langmuir-Hinshelwood.

Conclusions:

• Electrochemical steps and water are vital for ammonia formation.
• The study clarifies the distinct mechanisms for ammonia and nitrous oxide production.