Correlating Substrate Reactivity at Electrified Interfaces with the Electrolyte Structure in Synthetically Relevant...

Area of Science:

• Electrochemistry
• Materials Science
• Physical Chemistry

Background:

• Optimizing electrosynthesis involves complex chemical and physical parameters.
• Hybrid electrolytes utilize binary mixtures of organic solvents and water, enabling water as a reactant source.
• Understanding solvation in hybrid electrolytes is crucial for reaction control.

Purpose of the Study:

• To investigate how water-organic solvent interactions affect solvation properties in hybrid electrolytes.
• To demonstrate the control over aqueous domain size and composition.
• To elucidate the impact of these domains on electrosynthetic reaction kinetics and selectivity.

Main Methods:

• Synchrotron small-angle X-ray scattering (SAXS) to analyze domain structures.
• Molecular dynamics (MD) simulations with force fields to model interactions.
• Various spectroscopic techniques to probe solvation properties.
• Electrochemical experiments, including the hydrogen evolution reaction (HER).

Main Results:

• Modulating water-organic solvent interactions significantly alters solvation properties.
• Aqueous domain size and composition in hybrid electrolytes can be precisely controlled.
• Water reactivity in the HER is higher in aqueous domains, attributed to kinetics, not thermodynamics.
• Reaction kinetics are influenced by aqueous domains when water is activated first; selectivity may be affected for organic substrates reacting prior to water.

Conclusions:

• Fine-tuning aqueous domains in hybrid electrolytes opens new avenues for optimizing electrosynthesis.
• Understanding solvation effects is key to controlling reaction kinetics and selectivity.
• This knowledge is transferable to a wide range of electrosynthetic applications.