Polypyrrole Coated Thermally Exfoliated Graphite Nanoplatelets and the Effect of Oxygen Surface Groups on the Interaction of Platinum Catalysts with Graphene-Based Nanocomposites

Abstract

Expanded graphite oxide (GO) synthesized by graphite oxidation and thermal expansion was exposed to ultrasonic vibration to obtain graphite nanoplatelets (GNFs). Then, expanded GO as conductive filler was dispersed in polypyrrole matrix in order to be utilized as catalyst support. Electrical conductivities and polymer thickness of GNF-based composites were tailored at different feeding mass ratios. Thermal expansion led to the removal of oxygen functional groups on the surface, and the C/O ratio increased to 6. The highest C/O ratio had less hydrophilic carbon surface, and this decreased the interaction of Pt particles with support. When comparing Pt deposition behavior of GO, expanded GO, graphene nanosheets, and their composites, the results showed that Pt dispersion increased with increasing amount of oxygen functional groups on the surface of the samples. This workwas the first comprehensive and quantitative investigation on the relationship between Pt dispersion and surface oxygen functional groups of graphene-based nanocomposites.