A New Method for Calculating Rates of Molecules Adsorbing on Surfaces

Scientific Achievement

A new method based on molecular dynamics simulations and kinetic theory can predict the rate of molecules adsorbing to a surface from liquid. The method involves analyzing molecular positions and residence times and can be applied to any liquid-solid adsorption system.

Significance and Impact

Liquid-solid adsorption occurs in chemical reactions industrially and naturally.  This advance can enable more accurate modeling of catalytic reactions and the interactions of environmental

Research Details

• Liquid-solid adsorption is important in many fields. However, extraction of the intrinsic adsorption rates and the associated kinetic parameters is very challenging in both experiments and molecular dynamics simulations.
• Using methanol adsorption on a Pt(111) surface in water as a case study, geometric residence time distributions from molecular dynamics simulations were used to extract how often a molecule ‘encounters’ the surface and the probability of adsorbing per encounter.
• Simple algebraic equations were also provided that enable liquid-solid adsorption rates to be approximated for other systems even without simulation.