High-Activity, Durable Oxygen Reduction Electrocatalyst: Nanoscale Composite of Platinum−Tantalum Oxyphosphate on Vulcan Carbon

Abstract

A new oxygen reduction electrocatalyst for proton-exchange membrane fuel cells (PEMFCs) is synthesized by dispersing nanoscale Pt on a nanoscale tantalum oxyphosphate phase on a Vulcan carbon support, designated as Pt/[TaOPO4/VC]. Electrocatalytic activity is measured by the thin-film rotating disk electrode methodology in 0.1 M HClO4 electrolyte. The Pt/[TaOPO4/VC] electrocatalyst has a high mass-specific activity of 0.46 A mg−1Pt compared to 0.20 A mg−1Pt for a Pt/Vulcan carbon standard and has met the 2015 DOE goal of 0.44 A mg−1Pt. This tantalum-containing electrocatalyst is twice as durable as the standard Pt/carbon in terms of its loss of Pt electrochemical surface area after aggressive electrochemical cycling.