Characterization of Synthesized Carbon Nanomaterials from Coal

Abstract This paper examines the synthesis and characterization of carbon nano-materials derived from coal. Coal is an abundant carbon source that can serve as a precursor for economical, high-yield production of value-added carbon nano-materials. The purpose of this research was to synthesize carbon nanostructures from a coal sample using electro-chemical exfoliation (ECE) and chemical oxidation methods. The synthesized materials were characterized with techniques including SEM, FTIR, XRF, TGA, and ultimate/proximate analyses to determine coal type and investigate the nanostructures’ properties. Proximate and ultimate analyses identified the coal as a high grade, low volatile bituminous coal approaching meta-bituminous rank. This feed-stock possesses exceptional high carbon content (~83%) and heating capacity along with low sulfur and moisture. Two synthesis techniques were then applied to produce carbon nano-materials: (1) ECE using a DC voltage in a NaCl electrolyte suspension, and (2) chemical oxidation with H2SO4/HNO3 heating. SEM imaging revealed that the ECE product (sample A10) contained thin, wrinkled flakes up to 50 microns in size consistent with electro-chemical exfoliation and delamination. In contrast, the chemically oxidized product (A00) had smaller, jagged particles covered in pores reflecting more fracturing. FTIR spectra verified that by utilizing coal's natural aromatic structures, both processes generated novel carbonaceous nano-materials. Sample A00 caused faster peripheral group loss along with carbon consolidation, but sample A10 better conserved some functional groups. XRF revealed that sample purification was required due to residual reaction byproducts. The synthetic carbon nanostructures have considerably higher thermal stability than raw coal powder, according to TGA studies. Overall, this study used two synthesis approaches to successfully synthesize distinct carbon compounds from an abundant coal precursor. Although more refinement of purification techniques is necessary, the basic understanding of the formation of nanostructures and its controllable characteristics will enable a growing range of applications, including electronics, catalysis, and energy storage.