Adsorption and coupling of 4-aminophenol on Pt(111) surfaces

• Published in: Surface science 2016-04, Vol.646 (C), p.5-12
• Main Authors: Otero-Irurueta, G., Martínez, J.I., Bueno, R.A., Palomares, F.J., Salavagione, H.J., Singh, M.K., Méndez, J., Ellis, G.J., López, M.F., Martín-Gago, J.A.
• Format: Article
• Language: English
• Subjects: Adsorption; Aminophenol; Coupling; Coupling (molecular); DFT; Hydrogen atoms; Hydroxyl groups; Mathematical analysis; Oligomer; On-surface synthesis; STM; Surface chemistry
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2015.08.039

We have deposited 4-aminophenol on Pt(111) surfaces in ultra-high vacuum and studied the strength of its adsorption through a combination of STM, LEED, XPS and ab initio calculations. Although an ordered (2√3×2√3)R30° phase appears, we have observed that molecule–substrate interaction dominates the adsorption geometry and properties of the system. At RT the high catalytic activity of Pt induces aminophenol to lose the H atom from the hydroxyl group, and a proportion of the molecules lose the complete hydroxyl group. After annealing above 420K, all deposited aminophenol molecules have lost the OH moiety and some hydrogen atoms from the amino groups. At this temperature, short single-molecule oligomer chains can be observed. These chains are the product of a new reaction that proceeds via the coupling of radical species that is favored by surface diffusion. [Display omitted] •We have deposited 4-aminophenol on Pt(111) surfaces in ultra-high vacuum.•The adsorbed aminophenol molecules lose the H atom from the hydroxyl group at RT.•The system is driven by a strong surface–molecule interaction, similar to benzene.•Annealing above 420K, the deposited molecules lose the OH moiety and some hydrogen atoms from the amino.•Short single-molecule oligomer chains can be observed at STM above this temperature.