Template-free microwave-assisted fabrication of carbon dots/Zn(OH)2 composites for separation and enhancing chemical sensing

In this work, Zn(OH) 2 nanosheets embedded with carbon dots (CDs) were prepared through a template-free microwave-assisted route for the first time. The preparative strategy was facile, green and cost-effective. The final composites possessed uniform size distribution, good fluorescence property, excellent stability and fast adsorption ability for metal ions. A novel and ultrasensitive fluorescent assay has been proposed using CDs/Zn(OH) 2 composites as amplifying fluorescent sensors for rapid detection of Cu 2+ and Hg 2+ in real water samples. Aided by a Cu 2+ /Hg 2+ chelating agent, exclusive detection could be expected without cross-reactivity, as well as reversible and reproduced analysis. The detection limits were 0.3   nM for Cu 2+ and 0.2   nM for Hg 2+ , respectively. This assay could effectively enrich/separate and detect Hg 2+ and Cu 2+ simultaneously, revealing remarkable advantages including operational simplicity, high sensitivity, low cost and acceptable reproducibility.