Evolution from small sized Au nanoparticles to hollow Pt/Au nanostructures with Pt nanorods and a mechanistic study

Abstract

A facile method for synthesizing hollow Au/Pt nanostructures is reported; this strategy involves using small sized Au nanoparticles (NPs) as seeds and KI as growth modifier. Under polyvinylpyrrolidone (PVP) and potassium iodide (KI), small sized Au NPs evolved to plate-like nanostructures due to Ostwald ripening. The nanoplates served as templates for selectively growing Pt on {110} facets. Under high temperature, I⁻ was oxidized to I₂ by O₂. The formed I₂ and KI etched Au on {111}, generating hollow nanostructures. Through adjusting the reaction conditions, dendrite sphere-like nanostructures could also be prepared. The prepared bimetallic Au/Pt nanostructures exhibited high catalytic performance compared with sphere-like Pt.