ABSTRACT
Carbon quantum dots (CQDs) is an emerging category of carbonaceous substance engaging the broad scientific community due to good chemical stability, high dispersibility, biocompatibility, facile functionalization and low toxicity. CQDs are blended with certain specific photoluminescence properties showing upconversion phenomena. In upconversion photoluminescence, CQDs emit light of a shorter wavelength than the excitation source, which is especially employed for the generation of electron-hole pairs at the neighboring photocatalysts. These phenomena, thereby, empowered large bandgap photocatalysts to be functional under a broad spectral range. Excellent light-harvesting and high charge-transfer capability facilitate CQDs in various photocatalytic applications. The photo efficiency of CQDs can be tuned by varying size, dopant and functionalization on the surface and by heterojunction construction. This chapter focuses on demonstrating a current progression in the fabrications method followed by various applications of photocatalysis, such as photodegradation, hydrogen production and CO2 photoreduction. Various techniques, like arc discharge, laser ablation, electrochemical, acid-exfoliation, ultrasonic-exfoliation, hydrothermal, microwave, pyrolytic and template method, used to synthesize CQDs are also discussed. Furthermore, photocatalytic application of CQDs-based nanohybrids with a conclusion describing direction to achieve highly efficient, sustainable and environmentally friendly CQDs to provide the current state and new vision are elaborated. We hope the literature survey successfully distributes and recapitulates the information on CQDs.
