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

Abstract

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.

Lignin-based smart materials: a roadmap to processing and synthesis for current and future applications

“…More recently, Zhang et al also reported the preparation and LCQDs with bright green fluorescence from kraft lignin by a simple one-pot method. 91 In this case the prepared LCQDs revealed notable luminescence properties to be applied in cell imaging applications and also as ion detection sensors, with high sensitivity towards silver ion (Ag + ) ( Fig. 4c-e), comparable to those reported previously for other CQDs based on foodstuff precursors such as broccoli.…”

“…Lignin-based carbon quantum dots (LCQDs) have emerged as a new class of materials in applications such as metal ion sensors, bio-imaging and biosensors. 43,[86][87][88][89][90][91] Most of the sensors formulated on LCQDs work based on the quenching or the prevention of the quenching of fluorescence emission in the presence of certain analytes such as a metal ions. 92 Among the different quenching mechanisms, LCQDs work basically by static quenching pathways, where the interaction of LCQDs and a quencher (analyte) lead to the formation of a nonfluorescent ground-state complex, which alters the absorption spectrum of LCQDs, generating a quantifiable response.…”

“…92 Among the different quenching mechanisms, LCQDs work basically by static quenching pathways, where the interaction of LCQDs and a quencher (analyte) lead to the formation of a nonfluorescent ground-state complex, which alters the absorption spectrum of LCQDs, generating a quantifiable response. 91 LCQDs are characterized by a low cytotoxicity and a good biocompatibility, but perhaps one of the most appealing features is their low cost-production from non-food resources and relative easy manufacturing process in comparison to carbon quantum dots (CQDs) based on precursors such as citric acid, 93,94 gelatins 95 and chitosan 96,97 among others, 98,99 which generally require more complex reaction conditions than LCQDs.…”

Sustainable Synthesis of N‐Doped Hollow Porous Carbon Spheres via a Spray‐Drying Method for Lithium‐Sulfur Storage with Ultralong Cycle Life

“…Inspired by the above considerations, we have successfully developed a simple spray‐drying method to prepare N‐doped hollow porous carbon spheres (N‐HPCS) using biomass lignin as a carbon precursor because they widely exist in nature with high carbon content and plentiful chemical energy and cyanuric acid as an N dopant and a porogen [29] . The mass ratio of cyanuric acid to biomass lignin controls the lateral size, crystal structure, porosity, and pyrrolic‐N content.…”

Turning Spent Coffee Grounds into Sustainable Precursors for the Fabrication of Carbon Dots

“…These approaches make CDs a sustainable and non-toxic alternative to metal-based quantum dots. However, most available organic molecules are still expensive, and their use and/or synthesis can pose significant challenges to the environment and to human health [ 19 ]. It has become quite desirable to use biomass waste as alternative precursors in the synthesis of CDs [ 20 ], given that biomass waste material is ubiquitous, nontoxic, cheap and renewable [ 21 ].…”