Durability of Pt nanowire supported on carbon nanotubes under simulated start-up/shut-down conditions for polymer electrolyte membrane fuel cells

Abstract

The primary issue for the commercialization of proton exchange membrane fuel cells (PEMFCs) is the carbon corrosion of support and dissolution agglomeration of platinum nanoparticles under start-up/shut-down (SU/SD) conditions. Carbon nanotubes (CNTs)-supported Pt nanowire (PtNW) catalyst toward the ORR was synthesized via the soft template method. Electrochemical characterization demonstrated that the PtNW/CNTs showed higher activity than Pt/C because the anisotropy of the 1D structure strengthened its ability to transport electrons. An accelerated stressed test between 1.0 and 1.5 V for carbon corrosion was performed to examine durability at a single cell under practical SU/SD conditions. After 5000 cycles, the voltage drop was 0.142 V, and the voltage decay rate was 0.0284 mV cycle−1 for the PtNW/CNTs catalyst at 1600 mA cm−2; the voltage drop was 0.417 V, and the voltage decay rate was 0.0834 mV cycle−1 for the Pt/C catalyst at 1600 mA cm−2. The Pt/C catalyst demonstrated severe Pt nanoparticle aggregation and growth with a wide size distribution, whereas the PtNW/CNTs catalyst showed a slight variation. The PtNW/CNTs catalyst showed remarkable durability after 5000 SU/SD cycles. Consequently, PtNW/CNTs is a promising electrocatalyst, which can replace traditional Pt/C catalyst in PEMFCs.