Mobility and Bipolar Diffusion Charging Characteristics of Crumpled Reduced Graphene Oxide Nanoparticles Synthesized in a Furnace Aerosol Reactor

Abstract

Crumpled graphene oxide (CGO) nanoparticles were synthesized by atomizing a solution of graphene oxide sheets (GO) into a furnace aerosol reactor, in which GO was thermally reduced. By using a differential mobility analyzer (DMA), CGO nanoparticles of uniform mobility sizes were classified and collected. The morphology and sizes of these CGO nanoparticles were characterized by transmission electron microscope. The projected area equivalent size of CGO calculated from TEM images (offline measurements) was correlated to the electrical mobility size of CGO measured by a scanned mobility particle sizer system, which consisted of a DMA and a condensation particle counter (online measurements), and a reasonable match between the two sizes was observed. Further, the bipolar diffusion charging characteristics of CGO synthesized at different temperatures were studied with a tandem differential mobility analyzer system, from which the charge fractions of CGO were determined. The synthesis temperature affected the charge fractions of CGO with the same electrical mobility size, which was attributed to the different conductivities of CGO thermally reduced at different temperatures. CGO nanoparticles synthesized at 400 °C had the highest conductivity and the largest fraction of charged particles.