Surfactant assisted synthesis of Pt-Pd/MWCNT and evaluation as cathode catalyst for proton exchange membrane fuel cell

Abstract

This study evaluates the role of two types of surfactants, the anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) on the synthesis and properties of multi-walled carbon nanotube (MWCNT) supported bi-metallic Pt-Pd (atomic ratio 1:1) nanoparticles (NPs) and assess their performance as cathode catalyst in proton exchange membrane fuel cell (PEMFC). Pt-Pd/CNT catalysts are prepared through microwave assisted, polyol route in presence of SDS (Pt-Pd/CNT-S) or CTAB (Pt-Pd/CNT-C) and their performance is compared with Pt-Pd/CNT prepared in an identical way without any surfactant. The study shows the prominent influence of the type of surfactant in disaggregation of MWCNT bundles and the dispersion of Pt-Pd NPs on MWCNT support, which in turn controls their catalytic activity for oxygen reduction reaction. In-situ electrochemical characterization studies show improvement in the catalytic activity of Pt-Pd/CNT-S compared to Pt-Pd/CNT-C and Pt-Pd/CNT, demonstrating SDS as an efficient disperser for MWCNT. High fuel cell performance achieved with Pt-Pd/CNT-S having less Pt content (∼12 wt %) than the commonly employed pure Pt or Pt/C (20 wt %) catalysts demonstrates that it is a potential cathode catalyst for PEMFC that can help its wider commercialization.