Green synthesis of carbon quantum dots from corn stalk shell by hydrothermal approach in near-critical water and applications in detecting and bioimaging

[Display omitted] •The raw material of carbon quantum dots is waste biomass.•Near-critical water liquidation technology is non-toxic and pollution-free.•The method to prepare the carbon quantum has the great potential for mass production.•The carbon quantum dots we prepared have the excellent optical properties. Carbon quantum dots (CQDs) have diverse outstanding properties and potential application, but there are not many reports on the preparation of CQDs from agricultural waste without any addition of chemical reagent. Herein, a facile, economical and environmental route was developed for green synthesis of CQDs from corn stalk shell by hydrothermal approach in near-critical water. It’s worth noting that this method converted the biomass, which is regarded as agricultural wastes, into the carbon nano-materials with brilliant potential. The prepared CQDs present the great fluorescence property, the remarkable stability and biocompatibility, demonstrating this method is appreciate to produce the CQDs. The as-prepared CQDs can be employed in detecting and bioimaging domain, displaying distinctive potential for application. The superiorities of low-cost, renewability and sustainability drive the synthesis and applications of CQDs derived from biomass.