Perfluorosulfonic acid-functionalized Pt/carbon nanotube catalysts with enhanced stability and performance for use in proton exchange membrane fuel cells Original Research Article

To further improve lifetime and performance of carbon nanotube (CNT) supported Pt catalysts for proton exchange membrane fuel cells, perfluorosulfonic acid (PFSA) was introduced by a simple colloid route to functionalize Pt (PFSA-Pt/CNT) catalysts. Here the PFSA is available as a binder to tightly anchor Pt nano-particles onto the CNT surfaces, and as a proton conductor to increase the triple phase boundary zone of the catalysts. The prepared Pt nano-particles ranging from 2 to 5 nm in diameter are uniformly deposited on CNTs. A high catalytic activity of this novel composite catalyst was observed by both cyclic voltammetry and oxygen reduction reaction (ORR) measurements. The loss rate of the electrochemically active area of the PFSA-Pt/CNT catalyst decreases by a factor of two in comparison with that of the plain Pt/CNT catalyst. Meanwhile, a lower loss rate for the new catalyst was also observed by electrochemically-accelerated durability testing for the ORR activity. These results indicate that the stability of the new catalyst is significantly improved over that of the plain Pt/CNT catalyst by introduction of PFSA.