Development of durable platinum nanocatalyst on carbon nanotubes for proton exchange membrane fuel cells

Platinum nanocatalyst on multiwalled carbon nanotubes (MWCNTs) functionalized with citric acid (CA) was synthesized by a two-phase approach to transfer PtCl₆^2- from aqueous to organic phase. Pt-thiol ligand-based Pt/MWCNTs were fabricated with the presence of dodecanethiol (DDT). A homogeneous distribution as well as a uniform particle size of Pt particle was achieved by optimizing the CA and DDT contents. Pt/MWCNTs were examined by a high resolution transmission electron microscope for particle size and distribution. The Pt/MWCNT-based electrodes were characterized by electrochemical impedance spectroscopy for cell resistance and cyclic voltammetry (CV) for durability evaluation using humidified H₂ and N₂ gases at 80°C. The single-cell fuel cell performance with 0.2 (anode) and 0.4 mg (cathode) Pt cm^-2 evaluated using Nafion 212 electrolyte showed a power density of about 1520 mW cm^-2 with H ₂ and O₂ gases. The electrochemically active surface area, as measured by CV between 0.1 and 1.2 V, showed no degradation up to 1500 cycles for Pt/MWCNTs, showing exceptional durability.