Preparation and Electrochemical Capacitive Behavior of Graphene by Microwave Assisted Thermal Reduction of Graphite Oxide in Hydrazine Hydrate

Abstract

Graphene platelets with a large scale have been synthesized by reduction of graphene oxide (GO) in aqueous solution of hydrazine hydrate under microwave irradiation (MWI). Microstructure of the graphene was characterized by X-ray di®raction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM) together with the selected area electron di®raction (SAED). The electrochemical properties were evaluated by the analysis of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1 M Na 2 SO 4 aqueous solution. The results show that the as-prepared materials consist of crumpled, few-layer ($3 nm) thick and electronically conductive graphitic sheets. The supercapacitors fabricated using this material possess a low equivalent series resistance (ESR) value $1.6 and a high speci¯c capacitance of 285 F Á g À1 . In addition, the graphene reduced under a diverse duration of MWI displays a di®erent interlayer spacing, extent of reduction, level of graphitization and speci¯c capacitances. The duration of MWI and the treatment methods strongly a®ect the microstructure of graphene, and then dominate its electrochemical properties.

Liposome-induced exfoliation of graphite to few-layer graphene dispersion with antibacterial activity

“…3-4 nm. Since: (i) the sample is formed of graphene covered with variable amounts of phospholipids and is therefore a difficult sample to be analyzed by AFM due to the dependence of the AFM measurements on the roughness and cleanness of the surface, 68 (ii) the thickness of a phospholipid bilayer is around 0.4 nm, 69 (iii) stabilizers cannot touch the surface of graphene directly, 68,70 and a gap exists between phospholipids and graphene, and (iv) AFM measurements depend strongly on the substrate used for graphene deposition and are distorted by the variability of substrates, 68,71,72 these data supported the formation of fewlayer graphene, likely with not more than 2-3 layers. Fig.…”