Shape Changes of Pt Nanoparticles Induced by Deposition on Mesoporous Silica

GIOVANETTI, L.J.; JOSÉ M. RAMALLO-LOPEZ; FOXE, MICHAEL; JONES, LOUIS; MATTHIAS M. KOEBEL; GABOR A. SOMORJAI; ALDO F. CRAIEVICH; MIQUEL B. SALMERON; FÉLIX G. REQUEJO

SMALL

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2011 vol. 8 p. 468 - 473

1613-6810

Polyvinylpyrollidone (PVP)-capped platinum nanoparticles (NPs) are found to change shape from spherical to fl at when deposited on mesoporous silica substrates (SBA-15). Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and extended X-ray absorption fi ne structure (EXAFS) analyses are used in these studies. The SAXS results indicate that, after deposition, the 2 nm NPs have an average gyration radius 22% larger than in solution, while the EXAFS measurements indicate a decrease in fi rst neighbor co-ordination number from 9.3 to 7.4. The deformation of these small capped NPs is attributed to interactions with the surface of the SBA-15 support, as evidenced by X-ray absorption near-edge structure (XANES).