title: Heterogeneous Au-Pt nanostructures with enhanced catalytic activity toward oxygen reduction.
abstract: Heterogeneous Au-Pt nanostructures have been synthesized using a sacrificial template-based approach. Typically, monodispersed Au nanoparticles are prepared first, followed by Ag coating to form core-shell Au-Ag nanoparticles. Next, the galvanic replacement reaction between Ag shells and an aqueous H(2)PtCl(6) solution, whose chemical reaction can be described as 4Ag + PtCl(6)(2-)→ Pt + 4AgCl + 2Cl(-), is carried out at room temperature. Pure Ag shell is transformed into a shell made of Ag/Pt alloy by galvanic replacement. The AgCl formed simultaneously roughens the surface of alloy Ag-Pt shells, which can be manipulated to create a porous Pt surface for oxygen reduction reaction. Finally, Ag and AgCl are removed from core-shell Au-Ag/Pt nanoparticles using bis(p-sulfonatophenyl)phenylphosphane dihydrate dipotassium salt to produce heterogeneous Au-Pt nanostructures. The heterogeneous Au-Pt nanostructures have displayed superior catalytic activity towards oxygen reduction in direct methanol fuel cells because of the electronic coupling effect between the inner-placed Au core and the Pt shell.
authors.affiliation: Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Ye
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Weiwei
authors.initials: W
authors.lastname: Hu
authors.forename: Junyu
authors.initials: J
authors.lastname: Zhong
authors.forename: Yingying
authors.initials: Y
authors.lastname: Chen
authors.forename: Hongbin
authors.initials: H
authors.lastname: Cao
authors.forename: Jun
authors.initials: J
authors.lastname: Yang