Durability study of Pt/C and Pt/CNTs catalysts under simulated PEM fuel cell conditions

The durability of carbon black supported Pt (Pt/C) and multiwalled carbon nanotubes supported Pt (Pt/CNTs) catalysts for potential application in polymer electrolyte membrane fuel cells are investigated using an accelerated durability test. The electrochemical surface area of Pt/C degrades by 49.8% during the 192-h test time, compared with 26.1% for Pt/CNTs, which is due to Pt particle growth and Pt loss from the support in the form of Pt ions and Pt particles. Transmission electron microscopy and X-ray diffraction analysis show that Pt particles in Pt/CNTs present higher sintering resistance. X-ray photoelectron spectroscopy characterization indicates that CNTs in Pt/CNTs are more resistant to electrochemical oxidation than carbon black in Pt/C. It can be concluded that Pt/CNTs are more stable under electrochemical operation, which can be attributed to specific interaction between Pt and the support and the higher resistance of the support to electrochemical oxidation. (C) 2006 The Electrochemical Society.