Adhesion Energies of Liquid Hydrocarbon Solvents onto Pt(111), MgO(100), Graphene, and TiO2(110) from Temperature-Programmed Desorption Energies

Knowledge of the adhesion energy between a liquid solvent and a clean solid surface allows for a straightforward estimation of the decrease in the adsorption energy of reactant molecules on that surface due to the presence of that liquid solvent relative to gas-phase adsorption energies. Such estimations in turn can be used to aid the design of liquid-phase catalysts, electrocatalysts, and chemical separations. We report here adhesion energies for 13 liquid-on-solid systems involving alkane and aromatic hydrocarbon films on clean single-crystal surfaces estimated by using temperature-programmed desorption (TPD) measurements of their low-temperature adsorption energies versus coverage up through bulklike multilayer coverages. Because TPD is the most common experimental technique for measuring adsorption energies, the method employed here opens new opportunities for many other estimates of liquid/solid adhesion energies. The adhesion energies of various n-alkanes on MgO(100), graphene (on Pt(111)), and Pt(111) show that the adhesion energy (per unit area) of n-alkanes is nearly independent of chain length. Based on the adhesion energies of hexanes, we show that the adhesion energy changes significantly on different materials, increasing in the order of MgO(100) < graphene < TiO2(110) approximate to Pt(111).

Automated summary

Understanding the adhesion energy between a liquid solvent and a clean solid surface can help estimate the decrease in adsorption energy of reactant molecules on the surface, aiding in the design of liquid-phase catalysts and electrocatalysts. Adhesion energies for various liquid-on-solid systems were measured using temperature-programmed desorption, showing the potential for estimating other liquid/solid adhesion energies. The adhesion energies of n-alkanes on different materials varied, with the order of increase being MgO(100) < graphene < TiO2(110) approximately equal to Pt(111).