Single-Walled Carbon Nanotubes Supported Pt Electrocatalyst as a Cathode Catalyst of a Single Fuel Cell with High Durability against Start-up/Shut-down Potential Cycling

Carbon nanotubes (CNTs) have remarkable properties such as high conductivity, high porosity, and high oxidation resistance, which make them excellent candidates for supporting electrocatalysts in proton exchange membrane fuel cells (PEMFCs). In this study, high-crystallinity, high-purity single-walled carbon nanotubes (SWCNTs), which were prepared by enhanced direct injection pyrolytic synthesis (e-DIPS), were used as a support for a metal electrocatalyst. Platinum (Pt) nanoparticles of uniform size were synthesized by a facile solvothermal method and distributed evenly on the surface of the SWCNTs (Pt/SWCNT). Electrochemical measurements using cyclic voltammetry and linear sweep voltammetry showed that the Pt/SWCNT exhibited higher mass activity and specific activity compared to commercial Pt nanoparticles supported on graphitized carbon (Pt/C). A PEMFC membrane electrode assembly (MEA) utilizing Pt/SWCNT as the cathode layer (Pt/SWCNT-MEA) with low Pt loading demonstrated high-efficiency performance with power density per gram of Pt that was three times higher than that of Pt/C. Furthermore, in a durability test using a high-voltage triangular wave between 1.0 and 1.5 V to induce corrosion of the catalyst and carbon support, simulating harsh conditions of actual repeated start-up/shut-down cycles during long-term use, the Pt/SWCNT-MEA retained high performance even after 10,000 potential cycles. These results indicate that SWCNTs show promise as an excellent support material for electrocatalysts, offering high performance and durability, and thus can contribute to realizing PEMFCs with superior performance.