Generation of nitrogen-doped photoluminescent carbonaceous nanodots via the hydrothermal treatment of fish scales for the detection of hypochlorite

Preparing nitrogen-doped (N-doped) photoluminescent carbonaceous nanodots (C-dots) from the recycling/utilisation of nitrogen-rich carbonaceous waste has received considerable research interest. In this work, by using fish scales, an abundant food industry waste, as a starting material, we have developed a green, cheap and convenient approach for the preparation of N-doped photoluminescent C-dots, which represents a great potential for large-scale production. The as-synthesized C-dots are highly soluble, regularly sphere shaped and homogeneously sized with an average diameter of 2 nm. X-ray photoelectron spectroscopy results demonstrate that the nitrogen content can reach 14.6%, which is higher than that of most N-doped C-dots reported previously. The C-dots present a narrow photoluminescence emission band (400-490 nm) with a high quantum yield up to 17%, owing to the fluorescence enhancement effect of nitrogen doping. Besides, their fluorescence can be sensitively quenched by the addition of hypochlorite (ClO-), making them a promising sensing platform for ClO-.