Scalable Carbon Nanotube/Platinum Nanoparticle Composite Inks from Salt Templates for Oxygen Reduction Reaction Electrocatalysis for PEM Fuel Cells

Abstract

Platinum nanoparticles supported on multi-walled carbon nanotubes (CNTs) were synthesized by the chemical reduction of Magnus’s salt templates formed by the electrostatic stacking of oppositely charged platinum coordinated ions. The Magnus’s salt templated synthesis of platinum macrotubes, previously demonstrated, results in sidewalls made up of individual textured nanoparticles 100 nm in diameter and comprised of 5 nm diameter fibrils. Here we demonstrate a new platform method that utilizes the individual nanoparticles that make up the platinum macrotubes formed from salt templates and subsequently disperse them through a CNT network by ultrasonication to develop an electrocatalyst nanocomposite for the oxygen reduction reaction (ORR) critical for the development of proton exchange membrane (PEM) fuel cell applications. The structural morphology and composition of the nanocomposite catalysts was characterized using scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Raman spectroscopy to confirm the presence of platinum nanoparticles throughout the CNT network of the nanocomposite. The electrocatalytic activity of the nanocomposite inks was verified with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) for ORR. Furthermore, this all aqueous-based and scalable approach for the synthesis and dispersion of platinum nanoparticles with CNTs can lead to a new formulation process for the production of electrocatalytic nanocomposite inks for PEM fuel cells using the nanoparticles that form within salt templates after chemical reduction.