Shape changes of Pt nanoparticles induced by deposition on mesoporous silica.

Authors :: Giovanetti LJ
Ramallo-López JM
Foxe M
Jones LC
Koebel MM
Somorjai GA
Craievich AF
Salmeron MB
Requejo FG
Source :: Small (Weinheim an der Bergstrasse, Germany) [Small] 2012 Feb 06; Vol. 8 (3), pp. 468-73. Date of Electronic Publication: 2011 Dec 23.
Publication Year :: 2012
Abstract: Polyvinylpyrollidone (PVP)-capped platinum nanoparticles (NPs) are found to change shape from spherical to flat when deposited on mesoporous silica substrates (SBA-15). Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and extended X-ray absorption fine 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 first 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).<br /> (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)