Palladium silver nanoparticle catalysts synthesis on graphene via a Green Reduction in tea Solution for oxygen reduction reaction in PEM fuel cells

Abstract

The chemical reduction of graphe ne oxide (GO) and metal reduction  typically involves highly toxic reducing agents that are harmful to human health and environme nt, and complicated surface modification is often needed to avoid aggregation of the reduced GO during reduction process. This document presents large areas of graphene on carbon paper from graphite powder and anionic surfactant, assisted electrochemical exfoliation. Using a four-point probe technique, we found the conductivity of graphene on carbon paper to be 66 mS cm^-1 , which is approximately 1.2 and 1.65 times better than that of graphite coated carbon paper and carbon paper. Then PdAg  is reduced onto the graphene powder in the presence of green tea solution by making use of the reducing capability and the aromatic rings of tea polyphenol (TP) that contained in tea solution, that are used in oxygen reduction reaction (ORR) for PEM fuel cells. The electrochemically reduced PdAg is carefully characterized by ultra violet (UV-visible) and XRD. Their electrochemical properties are investigated with cyclic voltammetry, linear sweep voltammetry,. Particularly, XRD images show that the size of the nanoparticles reaches 5 nm.