Gravimetric Study on the CO and CO2 Adsorption Behaviour of Graphene Oxides.

MARTÍN ROBLE; MAXIMILIANO A. ZENSICH; GUSTAVO M. MORALES; D.E. DIAZ-DROGUETT

Termas de Chillán

Taller; TLMC2; 2016

Federación Latinoamericana de Materiales Carbonosos

Global warming, as a consequence of high emission of greenhouse gases, especially CO and CO2, has turned in the last years on a subject of general concern. Even though many new technologies have been proposed for CO2 capture, it?s nowadays believed that chemical absorption/adsorption is the most suited for industrial scale applications. Recently, nanomaterials based on carbon ?fullerenes, nanotubes and graphene- have appeared as possible solutions to many technological problems, due to their high specifc surface area, excellent mechanical and optical properties and good electrical and thermal conductivity. Particularly, graphene oxide (GO), a material derived from graphene, has a great potential to capture CO and CO2 if its surface chemistry is modifed or functionalized. In this work, CO and CO2 adsorption by sheets of GO and reduced graphene oxide (rGO) with different degrees of reduction, is evaluated by means of a crystal quartz microbalance (QCM). This technique is based on the relation between the resonance frequency of a fat crystal quartz (QC) and the gas mass adsorbed by the sample deposited on one side of the quartz crystal. The gas adsorption measurements are carried inside a vacuum chamber keeping the crystal temperature constant around 20ºC to minimize thermal noise on QC resonance frequency. Under these conditions, a gas pressure (CO or CO2) between 3 and 100 torr is injected into the chamber recording the QC resonance frequency changes in real time. Gas adsorption capacities of GO and rGO were studied as a function of the gas exposure pressure (CO or CO2). The GO and rGO samples were characterized by scanning electron microscopy and atomic force microscopy for morphological information, and by infrared and Raman spectroscopies for structural information. Results showed that the surface chemical characteristics of the graphene oxides plays a fundamental role on the CO and CO2 adsorption properties, and therefore, their control, modifcation or functionalization of their surface chemistry is of great importance on their gas adsorption performance and capacity.