Porous Platinum Nanotubes for Oxygen Reduction and Methanol Oxidation Reactions

Porous platinum nanotubes (PtNTs) with a all thickness of 5 nm, an outer diameter of 60 nm, and a length of 5-20 mu m are synthesized by galvanic displacement with silver nanowires, which are formed by the ethylene glycol reduction of silver nitrate. Oxygen reduction reaction (ORR) and durability experiments are conducted for PtNTs, Pt nanoparticles supported on carbon (Pt/C), and bulk polycrystalline Pt (BP-Pt) electrocatalysts to evaluate their catalytic properties for use as cathode catalysts in proton exchange membrane fuel cells. PtNTs demonstrate improved mass and specific activity for ORR and durability to Pt/C. Following durability testing, PtNTs exhibit specific ORR activity approaching that of BP-Pt. Catalyst activity for the methanol oxidation reaction (MOR) is characterized through cyclic voltammetry and chronoamperometry techniques to evaluate the materials for use as anode catalysts in direct methanol fuel cells. The PtNTs show improved specific activity for MOR and chronoamperometry characteristics over Pt/C and BP-Pt catalysts.