Palladium nanoparticle catalysts synthesis on graphene in sodium dodecyl sulfate for oxygen reduction reaction

Abstract

We prepare large areas of graphene on carbon paper from graphite powder and anionic surfactant, assisted electrochemical exfoliation as previous work. 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 palladium is electro-reduced onto the carbon paper based electrodes (with or without graphene) in absence or presence of different concentrations of sodium dodecyl sulfate (SDS), that are used in oxygen reduction reaction (ORR) for direct methanol fuel cells. The electrochemically reduced Pd is carefully characterized by scanning electron microscopy (SEM). Their electrochemical properties are investigated with cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. Particularly, SEM images show that the size of the nanoparticles decreases from 1000 to 70 nm as SDS concentration increases from 0 to 14 mM. The catalytic activities of graphene-supported Pd nanoparticles and Pd–carbon paper electro-catalysts for ORR are 112 and 2 Ag−1 Pd, which can reveal the particular properties of the exfoliated graphene supports and SDS media.