Modeling interfacial electric fields and the ethanol oxidation reaction at electrode surfaces

Area of Science:

• Surface Science
• Electrocatalysis
• Computational Chemistry

Background:

• Electrochemical environments at surfaces critically impact applications like batteries and electrocatalysis.
• Solvent, co-adsorbates, and electric fields are known to influence surface chemistry.
• Understanding these effects is crucial for advancing electrocatalysis research.

Purpose of the Study:

• To model key steps in the ethanol oxidation reaction (EOR) on a Rh(111) catalyst.
• To investigate the influence of electric fields and co-adsorbed water on EOR surface chemistry.
• To determine how these factors affect adsorption and reaction energies.

Main Methods:

• Density functional theory (DFT) modeling was employed.
• Simulations focused on the Rh(111) surface, a common EOR catalyst.
• Key reaction steps involving C-C and C-H bond scission and C-O bond formation were assessed.

Main Results:

• Electric fields and water presence significantly alter surface chemistry and energetics.
• C-C bond scission is most favored via CHCO adsorbates under specific conditions.
• While CHCO scission dominates without external fields, CH₂CO and CHCO scission become competitive under strong negative electric fields.

Conclusions:

• Electric fields and water play a crucial role in modulating the ethanol oxidation reaction mechanism.
• DFT simulations provide valuable insights into the complex interplay of these factors on catalyst surfaces.
• The findings contribute to a deeper understanding of electrocatalytic processes for fuel oxidation.