Simple Approach for Reconciling Cyclic Voltammetry with Hydrogen Adsorption Energy for Hydrogen Evolution Exchange...

Area of Science:

• Electrochemistry
• Computational Chemistry
• Materials Science

Background:

• Cyclic voltammetry (CV) is crucial for analyzing hydrogen evolution reaction (HER) kinetics.
• Accurate quantification of HER activity is essential for catalyst development.
• Existing models often require complex parameterization or lack universal applicability.

Purpose of the Study:

• To develop a quantum-scaled computational model for CV analysis of the HER.
• To establish a direct link between hydrogen adsorption free energy and HER kinetics.
• To resolve discrepancies in the analytical studies of HER mechanisms.

Main Methods:

• Development of a quantum-scaled CV model based on the Butler-Volmer relation for a one-step, one-charge transfer.
• Utilizing density functional theory (DFT) to calculate hydrogen adsorption free energy.
• Fitting the model to experimental CV data of elemental metals to determine a universal rate constant.

Main Results:

• The model successfully quantifies the exchange current density, a key descriptor of HER activity.
• A universal and absolute rate constant was derived and validated against experimental data.
• The model demonstrates that HER activity can be predicted solely from DFT-derived hydrogen adsorption free energy.

Conclusions:

• The quantum-scaled CV model provides a robust and computationally efficient method for HER activity prediction.
• This approach simplifies kinetic analysis and resolves long-standing controversies in HER research.
• The findings facilitate the rational design of advanced electrocatalysts for the HER.