1. Unusual reversibility in molecular break-up of PAHs: the case of pentacene dehydrogenation on Ir(111)
- Author
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Luca Bignardi, Silvano Lizzit, Alessandro Baraldi, Luca Sbuelz, Dario Alfè, Emil Sierda, Paolo Lacovig, Davide Curcio, Monica Pozzo, Curcio, D., Sierda, E., Pozzo, M., Bignardi, L., Sbuelz, L., Lacovig, P., Lizzit, S., Alfe, Dario, Baraldi, A., Curcio, Davide, Sierda, Emil, Pozzo, Monica, Bignardi, Luca, Sbuelz, Luca, Lacovig, Paolo, Lizzit, Silvano, Alfè, Dario, and Baraldi, Alessandro
- Subjects
Materials science ,Hydrogen ,Molecular dissociation ,dehydrogenation ,pentacene ,XPS ,photoemission ,chemical reactivity ,DFT ,graphene ,nanoribbons, PAH ,aromcatic hydrocarbons ,chemistry.chemical_element ,Photochemistry ,law.invention ,Pentacene ,chemistry.chemical_compound ,Adsorption ,law ,Molecule ,Dehydrogenation ,Benzene ,nanoribbons ,Graphene ,PAH ,General Chemistry ,Chemistry ,chemistry ,Carbon - Abstract
In this work, we characterize the adsorption of pentacene molecules on Ir(111) and their behaviour as a function of temperature. While room temperature adsorption preserves the molecular structure of the five benzene rings and the bonds between carbon and hydrogen atoms, we find that complete C–H molecular break up takes place between 450 K and 550 K, eventually resulting in the formation of small graphene islands at temperatures larger than 800 K. Most importantly a reversible temperature-induced dehydrogenation process is found when the system is annealed/cooled in a hydrogen atmosphere with a pressure higher than 5 × 10−7 mbar. This novel process could have interesting implications for the synthesis of larger acenes and for the manipulation of graphene nanoribbon properties., In this work, we characterise the adsorption of pentacene molecules on Ir(111) and their dissociation behaviour as a function of temperature.
- Published
- 2021