Synthesis and Photocatalytic Applications of Functionalized Carbon Quantum Dots

Abstract

Environmental degradation and energy shortages are becoming increasingly important as science and technology advance. Here, we review the photocatalytic approach of functionalized carbon quantum dots (CQDs) along with their up-converted photoluminescence behaviour, as well as their photoinduced electron transfer capabilities, opening a new path to effective metal-free photocatalyst. In this article, we are focusing on the recent invention of CQDs and CQD-based photocatalyst for environmental remediation such as dye degradation, CO2 conversion, and water splitting along with the categorization and synthesis of CQDs-derived photocatalysts, and applications for environmental concerns. Although it is essential to incorporate multiple perspectives, since CQDs and CQD-derived photocatalysts have varied perspectives to tackle unique environmental applications, our analysis is expected to offer additional details on CQD synthesis methods, tuning photocatalytic properties of CQDs with surface groups, and the mechanism of degradation of CQDs and CQD-based photocatalysts.

Photocatalytic One-Pot Conversion of Aldehydes to Esters and Degradation of Rhodamine B Dye Using Mesoporous Graphitic Carbon Nitride

“…The dyes are essential raw materials for industries, but once they are released into the environment, they cause harm to the ecosystem. The dye wastewater problems are overcome by dye degradation in various ways using numerous catalytic materials. − For dye degradation, use the chemically stable, non-toxic, low-cost photocatalytic g-C 3 N 4 , which is a prominent material for dye degradation . The g-C 3 N 4 material is a well-known material for various photodegradation studies. ,,,,, In the present study, along with the benzaldehyde esterification experiment, the as-prepared mpg-C 3 N 4 catalyst was also explored for the dye degradation study.…”

Photoluminescence Performance and Photocatalytic Activity of Modified Carbon Quantum Dots Derived from Pluronic F127

“…Secondly, •OH and •O 2 −1 formation causes the separation of e - /h + pairs, which transfer to the surface of the CQDs. Finally, •OH will act as an initiator for the photocatalytic degradation of organic dyes on the surface of CQDs [ 11 , 12 ]. Figure 5 gives the mechanism for the photocatalytic degradation of IC and LG SF dyes by CQDs.…”

“…Nevertheless, problems due to the high recoupling rates of photogenerated carriers (e.g., electrons and holes) and the inefficient utilization of sunlight in some photocatalytic devices remain unsolved. Fortunately, carbon quantum dots (CQDs) manifest the potential to address these issues [ 11 ]. Currently, the application of CQDs in the photocatalytic degradation of organic dyes is drawing the attention of many researchers [ 12 , 13 ].…”

“…The obtained NCQDs can degrade MB dye up to 98% after 150 min under visible light irradiation. For improving the photocatalytic degradation efficiency of organic dyes, the electronic structure of CQDs can be changed by elemental doping or surface modification to increase the electron conversion intensity in CQDs [ 11 , 27 ]. Hui et al [ 15 ] prepared heteroatom doped CQDs from rice husk by the hydrothermal method, and the N and Bi doped CQDs exhibited degradation rates of 72.16% and 68.91% for MB.…”

Conjugated photothermal materials and structure design for solar steam generation

“…For example, the absorption spectra can be predicted by density functional theory (DFT) calculations of the conjugated structures. This is an advantage over other carbon materials, even if they are of the same chemical composition [18][19][20][21][22]. We review the recent progress in the material development of conjugated solar absorbers based on (1) various molecular designs of small molecules and polymers, (2) absorber struc-tures from a thermal management perspective, and (3) applications to desalination, sterilization, wastewater treatment, and power generation.…”