Sustainable Synthesis of Bright Green Fluorescent Nitrogen-Doped Carbon Quantum Dots from Alkali Lignin

Sustainable, inexpensive, and environmentally friendly biomass waste can be exploited for large-scale production of carbon nanomaterials. Here, alkali lignin was employed as a precursor to synthesize carbon quantum dots (CQDs) with bright green fluorescence through a simple one-pot route. The prepared CQDs had a size of 1.5-3.5 nm, were water-dispersible, and showed wonderful biocompatibility, in addition to their excellent photoluminescence and electrocatalysis properties. These high-quality CQDs could be used in a wide range of applications such as metal-ion detection, cell imaging, and electrocatalysis. The wide range of biomass lignin feedstocks provide a green, low-cost, and viable strategy for producing high-quality fluorescent CQDs and enable the conversion of biomass waste into high-value products that promote sustainable development of the economy and human society.