Reversible Cyclic Voltammetry and Non-Unity Stoichiometry: The Ag/AgBr/Br^- Redox Couple

Area of Science:

• Electrochemistry
• Physical Chemistry
• Computational Chemistry

Background:

• Electrode reactions involving soluble reactants forming insoluble products are common in electrochemistry.
• Characterizing these reactions using voltammetry can be complex due to the phase change.
• Understanding the voltammetric waveshape is crucial for accurate analysis.

Purpose of the Study:

• To computationally simulate and experimentally investigate the voltammetry of reversible couples forming insoluble products.
• To characterize the voltammetric waveshape for such reactions.
• To analyze the apparent transfer coefficients derived from these reactions.

Main Methods:

• Computational simulations of electrochemical reactions.
• Experimental voltammetry using the silver/silver bromide (Ag/AgBr) redox couple.
• Analysis of voltammetric waveshape using apparent transfer coefficient analysis.

Main Results:

• The voltammetric waveshape for soluble reactant to insoluble product conversion was characterized.
• Apparent transfer coefficients significantly exceeding unity were observed.
• The study provides a generic insight into the characterization of these electrode reactions.

Conclusions:

• The voltammetry of reactions forming insoluble products yields apparent transfer coefficients greater than unity.
• This finding offers a new perspective for understanding and characterizing electrode reactions involving solid-phase products.
• The insights are applicable to a broad range of electrochemical systems with similar reaction mechanisms.