Structural Evolution of Solid Pt Nanoparticles to a Hollow PtFe Alloy with a Pt-Skin Surface via Space-Confined Pyrolysis and the Nanoscale Kirkendall Effect

A space-confined interfacial conversion approach is developed to directly transform 3 nm solid Pt nanoparticles into a 5 nm hollow PtFe alloy featuring a Pt-skin surface. The approach presented for the structural evolution from solid Pt NPs to hollow PtFe alloy with controlled size, structure, and composition can be applied to other multimetallic electrocatalysts.