Interfacial Cation Arrangement Controls Electrocatalytic Kinetics in CO₂ Reduction.

Area of Science:

• Electrochemistry
• Materials Science
• Physical Chemistry

Background:

• Electrolyte cation identity significantly impacts electrocatalytic activity.
• The precise arrangement of cations at the electrode interface is poorly understood.
• Organic cations offer tunable structures for systematic investigation.

Purpose of the Study:

• To investigate how interfacial cation arrangement affects electrocatalytic performance.
• To identify key variables controlling catalytic rates using organic cations.
• To understand the electrostatic effects of cations in electrocatalysis.

Main Methods:

• Rotating disk electrode (RDE) measurements.
• Electrochemical impedance spectroscopy (EIS).
• Molecular dynamics (MD) simulations.

Main Results:

• Smaller, densely packed phosphonium dications enhance CO2 reduction rates.
• Cation-electrode distance and interfacial density independently influence reactivity.
• Stronger interfacial electric fields lower the CO2 adsorption activation barrier.

Conclusions:

• Electrolyte cation arrangement is crucial for electrocatalytic kinetics.
• An electrostatic model explains cation effects in catalysis.
• Design principles for advanced electrolytes can be derived from these findings.