Synthesis of high fluorescence graphene quantum dots and their selective detection for Fe3+ in aqueous solution

Abstract

In recent years, carbon particles have gained numerous attentions because of their simple synthetic process, low toxicity and water solubility. The present work involves synthesis of two types of graphene quantum dots (GQDs) by treating sulfydryl group (−SH) amino acid glutathione (GSH) in the presence and absence of AgNO3 via one pot route, respectively. The Ag+ ions from AgNO3 can combine the −SH from GSH to form Ag2S, thus surfaces of the obtained graphene quantum dots (N-GQDs) are mainly modified by some free hydroxyl groups (OH), amino groups (NH2) and carboxyl groups (COOH). In the absence of Ag+ ions, the surfaces of as-prepared graphene quantum dots (SN-GQDs) not only include OH, NH2 and COOH, but also −SH. Interestingly, as-prepared two kinds of GQDs both have strong fluorescence with different emission wavelength. More importantly, these GQDs have special recognition ability for metal ions. The N-GQDs respond rapidly towards the presence of Fe3+ ions, and can be used as a probe to detect Fe3+ ions in waste water, while the SN-GQDs have a special recognition to Hg2+ ions.