High-yield production of g-C3N4 quantum dots as photocatalysts for the degradation of organic pollutants and fluorescent probes for detection of Fe3+ ions with live cell application

Graphitic-carbon nitride quantum dots (gCNQDs) have various fascinating properties and potential applications, but the low yield production of gCNQDs by current synthetic methods severely limits to exploit their properties and large-scale applications. Here we report the large scale synthesis of uniform gCNQDs through a combination of hydrothermal treatment, sintering and sonication methods for the first time. The production yield is up to 39 %, and the obtained gCNQDs dry powder possesses outstanding redispersibility, stability and water solubility in deionized water. The gCNQDs aqueous suspensions emit bright blue luminescence under UV excitation and can be an effective fluorescence probe for Fe3+ detection with good selectivity, sensitivity and photostability. The fluorescent probe shows low cytotoxicity and good cell-permeability, and then being successfully applied for the fluorescence imaging of Fe3+ in living cells. Moreover, the gCNQDs show the improved photocatalytic activity, which was evaluated by degradation of Rhodamine B and Methyl Orange. The large scale synthesis of gCNQDs with outstanding fluorescent properties, biocompatibility and photocatalytic properties can effectively facilitate the applications of gCNQDs and gCNQDs based nanocomposites in various fields.

Automated summary

Graphitic-carbon nitride quantum dots (gCNQDs) with outstanding properties and potential applications have been synthesized on a large scale using a combination of hydrothermal treatment, sintering and sonication methods. The production yield reached 39%, and the resulting gCNQDs exhibited excellent redispersibility, stability and water solubility. Additionally, the gCNQDs showed remarkable fluorescence properties, biocompatibility and photocatalytic activity, making them promising for various applications.