First-Principles Investigation of Adsorption of Ethene on a Twice Oxidized NiF₂ (001) Surface: A Model for the Simons...

Electrochemical fluorination on a nickel anode (Simons process) is an important process for producing fluorinated compounds. Despite its success, the mechanism is still under debate. Here a first-principles study is presented of fluorination of ethene on a model fluorinated (001) NiF ${}_2$ surface, which is chosen because it is stabilized under the external potential close to that at which the Simons cell operates and because it has a readily available ${\left[F_2\right]}^{-}$ unit providing fluorine source to aid fluorination reactions. The adsorption of the simplest double bond containing hydrocarbon on this surface is investigated. It is placed on the surface in different orientation, leading to six distinct structural outcomes upon relaxation. These include formation of 1,2-difluoroethane, fluoroethene, and 1,2-difluoroethene, alongside other fluorinated products as well as monocarbon fragments. This is one of the first computational studies of the catalytic Simons-type fluorination and can, despite its simplicity, offers some insight into reaction pathways and surface interactions.