Effect of a Au underlayer on outer-sphere electron transfer across a Au/graphene/electrolyte interface.

Area of Science:

• Surface Science
• Computational Chemistry
• Electrochemistry

Background:

• Investigating electron transfer at interfaces is crucial for electrochemical applications.
• Graphene and metal underlayers offer unique electronic properties for interface engineering.

Purpose of the Study:

• To theoretically investigate the impact of a gold underlayer on outer-sphere non-adiabatic electron transfer on graphene.
• To model energy level alignment and charge redistribution at the metal/graphene/redox electrolyte interface.

Main Methods:

• Utilized periodic and cluster Density Functional Theory (DFT) calculations.
• Developed a model for metal/graphene/redox electrolyte interfaces.
• Calculations performed for [Fe(CN)6]3-/4- and [Ru(NH3)6]3+/2+ redox couples.

Main Results:

• The gold underlayer significantly increases the electron transfer rate constant.
• Hybridization of gold electronic states with graphene wave functions enhances overlap with reactant orbitals.
• Electron transfer kinetics are primarily influenced by gold states, with minimal impact from graphene states.

Conclusions:

• Gold underlayers effectively promote electron transfer on graphene surfaces.
• Interface electronic structure modifications due to gold support are key to enhanced kinetics.
• The findings provide insights for designing advanced electrode materials for electrochemical systems.