Adiabatic versus non-adiabatic electron transfer at 2D electrode materials.
Dan-Qing LiuMinkyung KangDavid PerryChang-Hui ChenGeoff WestXue XiaShayantan ChaudhuriZachary P L LakerNeil R WilsonGabriel N MeloniMarko M MelanderReinhard J MaurerPatrick R UnwinPublished in: Nature communications (2021)
2D electrode materials are often deployed on conductive supports for electrochemistry and there is a great need to understand fundamental electrochemical processes in this electrode configuration. Here, an integrated experimental-theoretical approach is used to resolve the key electronic interactions in outer-sphere electron transfer (OS-ET), a cornerstone elementary electrochemical reaction, at graphene as-grown on a copper electrode. Using scanning electrochemical cell microscopy, and co-located structural microscopy, the classical hexaamineruthenium (III/II) couple shows the ET kinetics trend: monolayer > bilayer > multilayer graphene. This trend is rationalized quantitatively through the development of rate theory, using the Schmickler-Newns-Anderson model Hamiltonian for ET, with the explicit incorporation of electrostatic interactions in the double layer, and parameterized using constant potential density functional theory calculations. The ET mechanism is predominantly adiabatic; the addition of subsequent graphene layers increases the contact potential, producing an increase in the effective barrier to ET at the electrode/electrolyte interface.
Keyphrases
- electron transfer
- carbon nanotubes
- density functional theory
- high resolution
- label free
- ionic liquid
- molecular dynamics
- solid state
- gold nanoparticles
- single molecule
- molecular dynamics simulations
- high throughput
- room temperature
- high speed
- single cell
- risk assessment
- cell therapy
- walled carbon nanotubes
- climate change
- mass spectrometry