Platinum-based intermetallic nanotubes with a core-shell structure as highly active and durable catalysts for fuel cell applications

This paper describes the facile synthesis of the PtCu intermetallic nanotubes, which are obtained by a galvanic replacement reaction using Cu nanowires as templates followed by chemical etching and heat annealing. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy are used to characterize the PtCu intermetallic nanotubes. Both cyclic voltammetry and chronoamperometry results demonstrate that these PtCu nanotubes exhibit significantly high catalytic activity toward the formic acid oxidation reaction in comparison with the conventional Pt/C catalyst. Furthermore, the PtCu nanotubes show >10 times higher durability than the Pt/C catalyst in the accelerated ageing test. It is revealed that the PtCu intermetallic nanotubes have a Pt/PtCu core-shell nanostructure that combines the merits of tailorable electronic structures for core-shell nanoparticles and unique geometries for one-dimensional nanotubes, which synergistically contribute to the activity and durability. We believe that the design concept of hierarchy intermetallic nanotubes and the versatile synthetic strategy can not only be used for fuel cell catalysts but also be potentially extended to other catalysis fields.