Development of graphene supported catalyst nanoparticles for polymer electrolyte membrane (PEM) fuel cells

Official URL: http://risc01.sabanciuniv.edu/record=b1615035 (Table of Contents)

Catalyst nanoparticles inside PEM fuel cells are generally supported with a powdered material which has a high surface area, high mechanical and thermal stability, and preferably high conductivity. Vulcan®XC-72 which is a type of carbon black (CB) is the most conventional material that is used as catalyst support. It has a BET specific surface area of 250 m2.g−1 and conductivity of 4-7.4 S.cm-1. The usage of CB in fuel cells is beneficial in terms of this tempting features, however, the lack of tolerance to carbon monoxide (CO) poisoning due to the presence of deep cracks in its structure creates a great problem inside a harsh fuel cell environment. Graphene, on the other hand, provides a large surface area and high conductivity while providing a large and stable surface support as a result of its two dimensional structure. In this thesis study, the influence of using graphene derivatives (graphene oxide (GO), thermally reduced GO (TRGO) and graphene nanoplatelets(GNP)) as catalyst support materials to the catalytic activity of platinum (Pt) nanoparticles and fuel cell performance was evaluated in combination with the utilization of various platinum impregnation methods (ascorbic acid, ethylene glycol reflux, sodium borohydride reduction). The synthesized materials were characterized by using XRD, Raman, FTIR, TEM, SEM, Cyclic Voltammetry (CV), BET Surface Area Analysis, XPS and Fuel Cell Performance Test. Ethylene glycol method and GO were determined to be the most effective impregnation method and the best catalyst support candidate respectively. Ethylene glycol reflux was further applied to impregnate Pt on Vulcan®XC-72.The results were compared with commercial Vulcan®XC-72 supported Pt nanoparticles and synthesized Pt/ Vulcan®XC-72.