The impact of coal-borne impurities on coal-derived graphene quantum dots (GQDs) has been investigated on four U.S. coal ranks: lignite, subbituminous, bituminous, and anthracite. Preliminary characterization of the GQDs has been done using ultraviolet-visible spectroscopy (UV-vis) and UV fluorescence spectroscopy. GQDs produced from raw and clean coal samples exhibit differences in their optical properties. Higher UV-vis absorbances were observed from GQDs obtained from clean coal samples compared to those obtained from raw coal samples. In all cases, the photoluminescence emission spectra show an increasing redshift from lowest to highest coal rank. Excitation of anthracite-derived GQDs in the UV region produced little to no fluorescence signal, but a maximum emission signal was observed when excited in the visible region. These studies are relevant in tailoring specific optical applications of GQDs derived from different coal ranks.
Journal: TechConnect Briefs
Volume: TechConnect Briefs 2021
Published: October 18, 2021
Pages: 47 - 49
Industry sector: Advanced Materials & Manufacturing
Topics: Advanced Materials for Engineering Applications, Materials Characterization & Imaging