Preparation of photocatalysts decorated by carbon quantum dots (CQDs) and their applications: A review

Carbon quantum dots (CQDs), as a non-toxic and safe green material, exhibit good electron transport ability and up-conversion photoluminescence , which can be used to hinder the recombination of photogenerated electron-hole pairs and broaden the light absorption range. In recent years, remarkable progress has been made in the synthesis and application of CQDs decorated photocatalysts . In this paper, the precursor materials of CQDs and their physical and chemical properties are first introduced, and then the common preparation methods of CQDs decorated photocatalysts such as hydrothermal method , solvothermal method, calcination method, precipitation method and sol-gel method are mainly discussed. The effects of reaction conditions, precursor and reaction medium on particle size, morphology and molecular structure of CQDs decorated photocatalysts were summarized. In addition, the application and recent progress of CQDs decorated photocatalysts, including degradation of organic pollutants in water, production of hydrogen, and conversion of carbon dioxide into fuel, are reviewed. Finally, we put forward the challenges and suggestions for future research of CQDs decorated photocatalysts. • The precursors and physicochemical properties of CQDs were reviewed in this paper. • The development history of CQDs decorated photocatalysts was reviewed. • Five common preparation methods of CQDs decorated composite photocatalysts were summarized. • The application of CQDs decorated photocatalyst in energy and water pollution treatment is discussed. • The challenges and future research directions of CQDs decorated composite photocatalysts were pointed out.