A round dance of acetaldehyde molecular ensembles on Rh(111) surface; formation and decomposition of various paraldehyde conformers

The adsorption, desorption and polymerization of acetaldehyde (AA) on Rh(111) surface were studied by TDS, HREELS, work function measurements and theoretical calculations. Polymerization, as a new feature after adsorption of AA on Rh(111), makes the interpretation of the surface processes more exciting. The single molecule itself has at least two possibilities for adsorption on Rh(111) surface, namely eta(1) - (O) - CH3CHOa and eta(2) - (O, C) - CH3CHOa adsorption forms are considered. Moreover, eta(1) - (O) - CH3CHOa aldehyde molecules can react with each other forming oligomers or even longer polymers, as well. Paraldehyde, the triple molecular mass species of AA, shows some surprising kinetic and thermodynamic features on clean Rh(111) surface. However, the observed surface formation of the oligomer and its thermodynamically most stable gas phase conformer seems to be in contradiction. The interpretation of this phenomenon is the goal of the present study. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The adsorption, desorption and polymerization of acetaldehyde on the Rh(111) surface were investigated. It was found that acetaldehyde can polymerize on the surface, forming oligomers or longer polymers. The triple molecular mass species of acetaldehyde also exhibited interesting kinetic and thermodynamic features on the Rh(111) surface.