Synthesis and Characterization of Functionalized Graphene Oxide Frameworks for CO2 Adsorption

Abstract

Global Warming (GW) is the result of increased emissions of Green House Gases (GHG‟s) majorly is CO2 and CH4. CO2 is excreted in numerous industrial practices e.g. fossil fuel industries as well as new production plants like production of H2 gas from biowastes. Fossil fuel industries are the principal causes of CO2 emissions. The most suitable step towards the low CO2 concentrations on earth will be to decrease CO2 global emissions through the various industrial cleaners and other environment friendly manufacturing procedures. For that purpose, Post combustion methods are used to reduce the CO2 emissions which include capturing of CO2, then transportation and lastly storage in the underground earth crust and oceans. For capturing CO2, natural sources i.e. plants are not enough to remove CO2 in the atmosphere. So, in order to decrease the CO2 emissions in world, some other alternative substances must be synthesized, so that they are used for CO2 adsorption and reduction. Presently, GO based substances are being used widely due to their large surface areas. In this research work, 1,5-Naphthalene Diamine (NDA) and 1,4-Xylene Diamine (XDA) are used as linkers molecules for the synthesis of frameworks of graphene oxide (FGO) materials. GO-Cl was synthesized by simple method and both are confirmed by FTIR and XRPD. GO-Cl was more stable as compared to GO verified by TGA. Similarly, SEM analysis also confirmed the above synthesis. FGO materials are prepared by simple method of refluxing between graphene oxide (GO) 1,5- Naphthalene Diamine (NDA) as well as 1,4-Xylene Diamine (XDA) with different concentrations. These frameworks are verified by FTIR, which shows that secondary amines and secondary amides formation via interaction b/w linker molecules and different functional groups present on the surfaces and edges of GO. Enrichment of interlayer d-spacing is characterized by X-Ray powder diffraction (XRPD). The thermal stability and surface area of FGO materials has been enhanced as compared to precursor GO, which is verified by thermal gravimetric analysis (TGA) and micrometric BET surface area analyzer respectively. Framework containing linker 1,5-NDA is good as compared to other framework containing 1,4- XDA, that is confirmed by XRDP as there is more d-spacing in FGO-N-1 as compared to FGOX- 1. The surface area of FGO-N-1 is also more i.e. 489 (m2/g) as compared to FGO-X-1 i.e. 397.5 (m2/g). Hence, FGO-N-1 is more suitable for CO2 capturing. GO, FGO-N-1 and FGO-X-1 are adsorbed CO2 3.02, 5.61 and 4.04 % by weight respectively.