Multi-functional carbon dots from simple precursors: An excellent heavy metal ions sensor with photocatalytic activity in aqueous environment

Abstract

Carbon dots (CDs) with core and surface structures were prepared from simple precursors (ethylenediamine and ethylene glycol) by using house-hold microwave oven. The structural and optical properties were exclusively studied with HR-TEM, XRD, UV-Vis and PL techniques. The fluorescence emission of the CDs was predominantly dependent and/or independent on excitation-wavelength are owed to the existence of assorted functional groups on surface and uniform arrangement in core structure. Hence, the CDs shows better stability against photo bleaching and ionic strength. In addition, CDs are successfully used to detect heavy metal ions such as Cr6+ and Hg2+ selectively by fluorescence-based detection method through different quenching mechanisms with lower detection limit of 0.09 µM for Cr6+ and 0.16 µM for Hg2+. Similarly, we attempted rapid, simple and low cost on-field application by using two different cellulose-based filter papers for visual detection of Cr6+ and Hg2+ metal ions for quick and cheap method. Moreover, CDs were successfully employed for detoxification/degradation of Rhodamine B (RhB) dye and also 87 % degradation were achieved over the time period of 140 min under direct sunlight irradiation. At finally, the innovative CDs are superior multi-behavior material for the several environmental applications.