3D polyoxometalate-functionalized graphene quantum dots with mono-metallic and bi-metallic nanoparticles for application in direct methanol fuel cells

Abstract

A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. A facile and cost-effective catalysts have been developed on polyoxometalate (NaPWO) functionalized graphene quantum dots (GQDs) with several mono-metallic and bi-metallic nanoparticles such as platinum nanoparticles (PtNPs), palladium nanoparticles (PdNPs) and platinum-palladium nanoparticles (Pt-PdNPs). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) method. According to TEM images, the average particle sizes of PtNPs and PdNPs were found to be approximately 20-30 nm. The Pt-PdNPs/NaPWO/GQDs also exhibited a higher peak current for methanol oxidation than those of comparable PdNPs/NaPWO/GQDs and PtNPs/NaPWO/GQDs, thus providing evidence for its higher electro-catalytic activity. © 2016 The Electrochemical Society.