title: An in situ real-time x-ray diffraction study of phase segregation in Au-Pt nanoparticles.
abstract: In situ real-time x-ray diffraction was used to study phase segregation and coarsening of Au-Pt nanoparticles supported on silica powder, and porous alumina membranes. Contrary to the expectations from the bulk phase diagram, silica supported Au-Pt nanoparticles have an alloyed structure that is preserved even after extensive annealing at temperatures as high at 700 degrees C. In stark contrast, alumina supported Au-Pt nanoparticles exhibit a rich phase behaviour that is sensitive to alloy composition and the details of the synthesis process. In particular, low-density as-prepared Au(41)Pt(59) nanoparticles exhibit the signature of incipient phase segregation that develops into full phase separation during annealing at high temperature.
authors.affiliation: Physics Department, Binghamton University, Binghamton, NY 13902, USA. omalis@purdue.edu
authors.forename: O
authors.initials: O
authors.lastname: Malis
authors.forename: M
authors.initials: M
authors.lastname: Radu
authors.forename: D
authors.initials: D
authors.lastname: Mott
authors.forename: B
authors.initials: B
authors.lastname: Wanjala
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.forename: C-J
authors.initials: CJ
authors.lastname: Zhong
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003199:Computer Systems; D003460:Crystallization / Q000379:methods; D006046:Gold / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D044367:Phase Transition; D010984:Platinum / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D003102:Colloids; D046911:Macromolecular Substances; D010984:Platinum; D006046:Gold