SERS on (111) Surface Nanofacets at Pt Nanoparticles: The Case of Acetaldehyde Oxime Reduction

• Published in: Journal of physical chemistry. C 2012-05, Vol.116 (19), p.10781-10789
• Main Authors: Vidal-Iglesias, Francisco J, Solla-Gullón, José, Orts, José M, Rodes, Antonio, Pérez, Juan M, Feliu, Juan M
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron states; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Methods of electronic structure calculations; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp300748f

This work shows that SERS spectra can be used to monitor a surface reaction that exclusively takes place on certain surface sites of Pt nanoparticles. As an example, the reduction of acetaldehyde oxime (AO) toward ethylamine on platinum in perchloric acid solutions, which is a structure-sensitive process that takes place exclusively on (111) sites, is employed. Spherical and octahedral-tetrahedral Pt nanoparticles were used as SERS-active material. The AO reduction, followed by SERS measurements, was clearly observed on the octahedral-tetrahedral Pt nanoparticles due to their preferential (111) surface orientation. In addition, FTIRS and DFT theoretical calculation analyses were performed. From spectroelectrochemical results and DFT calculations, it is concluded that AO is bonded to the (111) platinum surfaces by the lone pair of the N atom, in a top adsorption configuration, with the molecular plane perpendicular to the metal surface. In addition, SERS spectra also showed that acetonitrile, produced by dehydration of AO, is adsorbed on (111) sites at E ≤ 0.4 V. Results reported in this work show that the combination of the SERS activity of platinum nanoparticles and the use of preferentially oriented nanoparticles allows SERS studies of structure-sensitive reactions.