Applied Surface Science, Vol.358, 84-90, 2015
Decoration of crumpled rGO sheets with Ag nanoparticles by spray pyrolysis
In this work, crumpled reduced graphene oxide (rGO) nanostructures were produced using spray pyrolysis technique. Graphite oxide (GtO) prepared through a modified Hummers method was used as starting material. Water dispersions of graphene oxide (GO) were prepared and sprayed in a tube furnace at 300 degrees C, 500 degrees C and 700 degrees C using Argon (Ar) as carrier gas. Also, precursor dispersions with different AgNO3 concentrations were processed at the same conditions. During the treatment, the sprayed droplets underwent rapid heating and then gradual cooling until the exit of the oven, where crumpled rGO and Ag/rGO powders were collected. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and FT-IR spectroscopy. It was established that the crumpling of the nanosheets was slightly affected by the increase of the process temperature. Crumpled morphologies were obtained even at low temperature of 300 degrees C. In contrast, the degree of GO reduction was temperature dependent and increased with the increase of the temperature. The incorporation of Ag nanoparticles was evidenced by the XRD and TEM analysis with the size of the Ag nanoparticles to grow as the concentration of AgNO3 and/or the process temperature increased. SERS effect in the Raman spectra of the Ag/rGO materials was observed that reached a maximum at 500 degrees C. Spray pyrolysis was suggested as a simple, controllable and scalable route for the instantaneous crumpling, reduction and decoration of GO nanosheets with metal/metal oxide nanoparticles. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Spray pyrolysis;Crumpled graphene oxide;Reduced graphene oxide;Silver nanoparticles;Decoration