Carbon and graphene quantum dots are prepared using top-down and bottom-up methods. Sustainable synthesis of quantum dots has several advantages such as the use of low-cost and non-toxic raw materials, simple operations, expeditious reactions, renewable resources and straightforward post-processing steps. These nanomaterials are promising for clinical and biomedical sciences, especially in bioimaging, diagnosis, bioanalytical assays and biosensors. Here we review green methods for the fabrication of quantum dots, and biomedical and biotechnological applications.

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Green synthesis, biomedical and biotechnological applications of carbon and graphene quantum dots. A review

Abstract As an emerging material, nanomaterials have attracted extensive attention due to their small size, surface effect and quantum tunneling effect, as well as potential applications in traditional materials, medical devices, electronic devices, coatings and other industries. Herein, the influence of nanoparticle selection, production process, grain size, and grain boundary structures on the mechanical properties of nanomaterials is introduced. The current research progress and application range of nano-materials are presented. The unique properties of nano-materials make them superior over traditional materials. Therefore, nanomaterials will have a broader application prospect in the future. Research on nanomaterials is significant for the development and application of materials science.

https://www.degruyter.com/document/doi/10.1515/ntrev-2020-0021/pdf

Mechanical properties of nanomaterials: A review

Synthesis of graphene quantum dots from natural polymer starch for cell imaging

A brief review on supercapacitor energy storage devices and utilization of natural carbon resources as their electrode materials

Carbon-based quantum particles, especially spherical carbon quantum dots (CQDs) and nanosheets like graphene quantum dots (GQDs), are an emerging class of quantum dots with unique properties owing to their quantum confinement effect. Many reviews appeared recently in the literature highlighting their optical properties, structures, and applications. These papers cover a broad spectrum of carbon-based nanoparticles, excluding a more detailed discussion about some important aspects related to the definition of carbon-based particles and the correlation of optical and electrochemical aspects in relation to sensing and biomedical applications. A large part of this review is devoted to these aspects. It aims, in particular, to act as a bridge between optical and electrochemical aspects of carbon-based quantum particles, both of which are associated with the electronic nature of carbon-based quantum particles. A special focus will be on their use in electroanalysis, notably their benefits in redox, and in electrochemical analysis with emphasis on their application as sensors. Electroanalysis is an easy and cost-effective means of providing qualitative and quantitative information of a specific analyte in solution in a time scale of some minutes. The integration of carbon-based quantum particles into these detection schemes as well as their incorporation into composite nanomaterials have largely improved detection limits with possibilities for their integration in aspects ranging from point-of-care devices to personalized medicine. This review will focus on some of these aspects while also covering the nanomedical aspects of carbon-based quantum particles, ultimately correlated for such developments.

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Carbon-based quantum particles: an electroanalytical and biomedical perspective.

Abstract As a new class of fluorescent carbon materials, graphene quantum dots (GQDs) have attracted tremendous attention due to their outstanding properties and potential applications in biological, optoelectronic, and energy-related fields. Herein, top-down and bottom-up strategies for the fabrication of GQDs, mainly containing oxidative cleavage, the hydrothermal or solvothermal method, the ultrasonic-assisted or microwave-assisted process, electrochemical oxidation, controllable synthesis, and carbonization from small molecules or polymers, are discussed. Different methods are presented in order to study their characteristics and their influence on the final properties of the GQDs. The respective advantages and disadvantages of the methods are introduced. With regard to some important or novel methods, the mechanisms are proposed for reference. Moreover, recent exciting progresses on the applications of GQD, such as sensors, bio-imaging, drug carriers, and solar cells are highlighted. Finally, a brief outlook is given, pointing out the issues still to be settled for further development. We believe that new preparation methods and properties of GQDs will be found, and GQDs will play more important roles in novel devices and various applications.

/pdf/synthesis-and-applications-of-graphene-quantum-dots-a-review-2e1fdg4z8w.pdf

Synthesis and applications of graphene quantum dots: a review

Green Synthesis of Graphene Quantum Dots from Cotton Cellulose

Hydrolysis of NH3BH3 and NaBH4 by graphene quantum dots-transition metal nanoparticles for highly effective hydrogen evolution

Achieving the controlled release of H2 through an effective approach still faces many challenges. Herein, high-quality graphene quantum dots (GQDs) are synthesized from a new precursor, 1,2,4-trihydroxy benzene, and a multifunctional platform of Rh@GQDs is further developed for the controlled H2 evolution upon the hydrolysis of NH3BH3 (AB). More importantly, the designing concepts of multistep and stepless speed controls have been introduced in the domains of both H2 evolution for the first time. Through a novel designing protocol, the rate of H2 evolution can be freely regulated and constantly varied on demand by means of chelation between Zn2+ and ethylene diamine tetraacetic acid (EDTA). The density functional theory calculation indicates that Zn2+ has the priority to be adsorbed onto Rh(100) due to its larger adsorption energy (107.98 kcal·mol-1) than that of AB (36.36 kcal·mol-1). A controlling mechanism is presented such that Zn2+ will cover the active sites of the nanocatalyst to prevent the H2 evolution, and EDTA can chelate Zn2+ to reactivate the nanocatalyst for the production of H2, greatly facilitating use of this strategy in other catalytic reactions. Moreover, it is demonstrated that the protocol is equally valid for diverse hydrogen storage materials. Therefore, this work not only establishes whole new concepts for the controlled production of H2 but also explains their mechanism, thus remarkably advancing the utilization of H2 energy and significantly enlightening the controlled process of catalysis.

Demonstration of Controlled Hydrogen Release Using Rh@GQDs during Hydrolysis of NH3BH3.

Graphene quantum dots (GQDs) have aroused widespread attention because of their remarkable properties and potential applications. Herein, we discuss both the top-down and bottom-up strategies for t...

Guo Lv

Papers

Synthesis and applications of graphene quantum dots: a review

Green Synthesis of Graphene Quantum Dots from Cotton Cellulose

Hydrolysis of NH3BH3 and NaBH4 by graphene quantum dots-transition metal nanoparticles for highly effective hydrogen evolution

Demonstration of Controlled Hydrogen Release Using Rh@GQDs during Hydrolysis of NH3BH3.

A Critical Review of Graphene Quantum Dots: Synthesis and Application in Biosensors