Graphite Oxide and Its Related Materials for Supercapacitors and Gas Sensors

Graphite oxide and related materials (reduced graphite oxide, graphite nanoplatelets) were synthesized using various techniques and studied as electrodes for supercapacitors. Graphite oxide was synthesized from high purity graphite using modified Hummers method. Reduction of graphite oxide was carried out using the method of dynamic heating with controlled heating rate. Graphite nanoplatelets were obtained by means of ultrasonication of porous reduced graphite oxide. Graphite oxide and related materials were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, etc. It was determined that graphite oxide possesses higher capacity (65 F/g at 2mV/s) compared to other materials. The reduction of graphite oxide decreases the capacity of supercapacitors, and it confirms the dominant role of oxygen-containing functional groups in the formation of supercapacitors’ characteristics. High graphitization degree of graphite nanoplatelets prevents the formation of double-electric layer and they possess relatively low ($0.4-1.6 \mathrm{~F} / \mathrm{g}$) despite their high conductivity, and they can be used only after chemical functionalization of surface. The reduction of graphite oxide led to decrease of ammonia gas sensing characteristics.