Facile and High-Yield Synthesis of Carbon Quantum Dots from Biomass-Derived Carbons at Mild Condition

Abstract

Hydrothermal synthesis of carbon quantum dots (CQDs) from biomass is a green and sustainable route for CQDs applications in various fields. However, one of the major problems is the low CQDs yield because the traditional hydrothermal treatment would produce large amounts of hydrochar byproduct. In this work, we present a novel, facile, and effective method for large-scale synthesis of CQDs from biomass-derived carbon including hydrochar and carbonized biomass through mild oxidation (NaOH/H2O2 solution). An ultrahigh CQDs yield of 76.9 wt % can be obtained, which is much higher than those obtained from traditional hydrothermal and strong acid oxidation processes. Furthermore, the CQDs have excellent quantum yield (QY) that is higher than (or comparable to) those from other methods. In addition, the CQDs have uniform size (∼2.4 nm) and their surface states can be regulated to significantly improve the QY by adjusting the concentration of oxidants. The CQDs displayed excellent sensitivity for Pb2+ detection along with good linear correlation ranging from 1.3 to 106.7 μM. These advantages, together with low cost, sustainability, and green process, make this approach have great potential in the synthesis and applications of CQDs in large scale.

Evaluation of Different Bottom-up Routes for the Fabrication of Carbon Dots

“…The reaction yields obtained were satisfactory in the case of microwave-and calcination-assisted syntheses with 31.6% and 26.1%, respectively. In fact, the obtained synthesis yields for those two CDs are in line with values obtained in studies aiming to high-yield synthesis of CDs [49]. Unfortunately, the synthesis yield for hydrothermal-CDs was quite low (1.5%), which indicates that this type of bottom-up route is not appropriated for high-yield synthesis.…”

Efficient White Electrochemiluminescent Emission From Carbon Quantum Dot Films

“…Yields of synthesis were measured by comparing the weight of starting precursors to the weight of the final CQD product and were found to be between 27 and 35%. An important factor for light emitting materials is the bulk low-cost synthesis of the product (Jing et al, 2019 ). This synthesis procedure created gram-scale CQDs with constant oven settings and constant starting solutions providing ideal conditions for scaling up synthesis of CQDs with tunable light emitting properties.…”

Carbon and graphene quantum dots: a review on syntheses, characterization, biological and sensing applications for neurotransmitter determination

“…Notably, the high resolution TEM image reveals lattice fringes with 0.20 nm of inter-planar space that is corresponding to the facet of graphitic carbon. 84 Lee et al introduced a newly devised procedure which is used for synthesizing the size controlled single crystalline GQDs in hexagonal shapes. 85 In addition, the smooth size distribution and the crystalline forms have been seen using the images obtained from TEM with a lateral size of respectively 5 nm ( Fig.…”