XAFS studies of Au and Au@Ag nanoparticles in aqueous solutions
Abstract
We have studied Au, and Ag shells deposited on core Au (Au@Ag) nanoparticles using x-ray absorption fine structure (XAFS). Several interesting optical and structural observations of these nanoparticles prompted us to explore the local structures around Au and Ag atoms. In this report, we focus on two issues: (i) How does the local structure change upon decreasing the particle size, and how could this be manifested in changes in bond lengths, bond-length disorder, etc? (ii) How does the particle size affect the interface between the core and shell regions of the Au@Ag nanoparticles, e.g. the tendencies towards phase separation or alloying? Most of the earlier XAFS studies were performed on nanoparticles on solid supports. Here our nanoparticles are prepared by radiolytically-initiated reduction of Ag and Au ions and suspended in aqueous solution, thus suitable to study their intrinsic properties in their natural in-situ environment. We will present XAFS results for the nanoparticles at various sizes and discuss these issues.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2001
- Bibcode:
- 2001APS..MARL11006S