Substrate‐Free Microwave Synthesis of Graphene

M. Frenklach, A. Dato
University of California, Berkeley, US

Keywords: graphene, nanoparticle

Summary:

Graphene, an atomically thin sheet of carbon atoms tightly packed in a two‐dimensional honeycomb lattice, possesses many extraordinary properties and its potential applications have recently been the subject of intense scientific interest. Obtaining graphene sheets of high quality in commercial quantities remains a challenge. We will review a substrate‐free method for synthesizing graphene sheets in the gas phase using an atmospheric‐pressure microwaveplasma reactor. Graphene is produced through the delivery of liquid (most successfully ethanol) droplets into argon plasma. The produced carbonaceous materials were characterized by transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, and electron diffraction—all techniques showing the presence of high‐quality graphene. We investigated the influence of the applied microwave power, flow rates through microwave reactor, and starting hydrocarbon precursors on the graphene production. The results are interpreted in terms of possible mechanistic models of graphene growth, suggesting possible direction for improved synthesis of high‐quality graphene.