Potential of Zero Charge as a Kinetic Descriptor for CO₂ Electroreduction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalyst design traditionally uses binding energies, but overlooks potential-dependent surface charging.
• This limitation hinders accurate prediction of reaction kinetics under operational conditions.

Purpose of the Study:

• To identify a new kinetic descriptor for electrocatalysis that accounts for surface charging.
• To investigate the role of the potential of zero charge (PZC) in CO2 electroreduction.

Main Methods:

• Evaluated 11 catalysts across a wide pH range (acidic to alkaline).
• Utilized electrochemical analysis, isotope labeling, in situ spectroscopy, and computational modeling.
• Correlated overpotential with PZC for various CO2 electroreduction pathways.

Main Results:

• Identified the potential of zero charge (PZC) as a key kinetic descriptor.
• Demonstrated strong correlations between overpotential and PZC for CO, formate, and multicarbon products.
• Showed PZC fundamentally regulates electron-transfer kinetics by influencing interfacial electron energy.

Conclusions:

• The PZC is a crucial descriptor for understanding and designing electrocatalysts.
• PZC-based descriptors improve predictions for CO2 electroreduction and hydrogen evolution reactions.
• This descriptor offers broad applicability across diverse electrocatalytic systems.