A Method for Obtaining Liquid-Solid Adsorption Rates from Molecular Dynamics Simulations: Applied to Methanol on...

Area of Science:

• Chemical Engineering
• Physical Chemistry
• Surface Science

Background:

• Adsorption is crucial in heterogeneous catalysis, influencing reactant molecule participation in surface reactions.
• Gas-solid adsorption rates are well-understood, but liquid-solid adsorption rates remain less studied.
• Liquid-phase solvent dynamics complicate experimental and theoretical analysis of liquid-solid adsorption.

Purpose of the Study:

• To develop a molecular dynamics (MD) simulation method for studying liquid-solid adsorption rates.
• To quantify the adsorption rate of methanol onto a platinum surface from an aqueous solution.
• To provide a generalizable tool for predicting adsorption rates in diverse liquid-solid systems.

Main Methods:

• Utilized molecular dynamics (MD) simulations to model solute diffusion in a liquid solvent.
• Simulated the adsorption process of methanol molecules in an aqueous environment onto a Pt(111) surface.
• Applied a random walk model approximation to describe solute displacement rates for state identification.

Main Results:

• Successfully discerned and quantified adsorbed and non-adsorbed states of methanol near the Pt(111) surface.
• Extracted key adsorption parameters, including the sticking coefficient.
• Determined a macroscopically relevant adsorption rate for the liquid-solid system.

Conclusions:

• The developed MD method effectively quantifies liquid-solid adsorption rates.
• This methodology offers a versatile approach applicable to various reactants, surfaces, and liquid environments.
• Enables accurate prediction of adsorption kinetics, advancing heterogeneous catalysis research.