Modulation of red-light emission from carbon quantum dots in acid-based environment and the detection of chromium(Ⅲ)ions

ⅢIn this study,the carbon quantum dots,which can emit sharp red light(R-CQDs)under optical excitation,were synthesized via simple heat treatment of wine lees.The features of the photoluminescence(PL)emission from R-CQDs in solutions with different p H values and with metal ions were examined.The intensity of the PL emission from R-CQDs depends sensitively on the p H values of the solutions with the R-CQDs.Interestingly,the p H-response of the PL intensity is reversible and can be enhanced linearly in the p H value range from 4 to 12,indicating that the R-CQDs can be applied for the p H sensor.Furthermore,the quench of the PL emission from R-CQDs can be observed when adding chromium(Ⅲ)ions into the solution with R-CQDs.This effect can be utilized for selective and quick detection of chromium(Ⅲ)ions in solutions simply via the standard PL measurement.The interesting and important findings from this work can be applied to explore more practical applications of the CQDs prepared cheaply and easily.

A metal-free composite photocatalyst of graphene quantum dots deposited on red phosphorus

A simple approach to enhance the photocatalytic activity of red phosphorus（P） was developed.A mechanical ball milling method was applied to reduce the size of red P and to deposit graphene quantum dots onto red P. The product was characterized by scanning electron microscopy, transmission electron microscopy, contact angle measurements, zeta-potential measurements, X-ray diffraction and UV–vis absorption spectroscopy. The product exhibited high visible-light-driven photocatalytic performance in the photodegradation of rhodamine B.

Lignin-derived dual-function red light carbon dots for hypochlorite detection and anti-counterfeiting

The efficient utilization of natural lignin,which is the main by-product of the cellulose industry,is crucial for enhancing its economic value,alleviating the environmental burden,and improving ecological security.By taking advantage of the large sp2 hybrid domain of lignin and introducing amino functional groups,new lignin-derived carbon dots(SPN-CDs)with red fluorescence were successfully synthesized.Compared with green and blue fluorescent materials,red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability.The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite.Considering this feature,a portable,low-cost,and sensitive fluorescence sensing paper with a low limit of detection of 0.249μmol∙L^(–1) was fabricated using the SPN-CDs for hypochlorite detection.Furthermore,a new type of visible-light and fluorescence dual-channel information encryption platform was constructed.Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus,as well as an information“eraser”,facilitating a safe and diversified transmission and convenient decryption of information.This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.