Semiconductor photocatalysis has become an increasing area of interest for use in water treatment methods. This review systematically presents the recent developments of emerging semiconductor photocatalysis system and their application in the removal of water pollutants. A brief overview of the semiconductor photocatalysis mechanism involved with the generation of reactive oxygen species (ROS) is provided first. Then a detailed explanation of the development of TiO₂-based, g-C₃N₄-based, and bismuth-based semiconductor materials and their applications in the degradation of water pollutants are highlighted with recent illustrative examples. Furthermore, the future prospects of semiconductor photocatalysis for water treatment are critically analyzed.

We report the surprising chemiluminescence (CL) behavior of fluorescent carbon dots in the presence of a strong alkaline solution, such as NaOH or KOH. The CL intensity was dependent on the concentration of the base and carbon dots in a certain range. A possible CL mechanism was studied by UV-Vis, fluorescence, CL, FTIR, XPS and EPR spectroscopy. Radiative recombination of the injected electrons by “chemical reduction” of carbon dots with thermally excited generated holes was proposed, which sheds new light on the characteristics of carbon dots.

Surface long-lived O ₂ ˙ ⁻ were verified in photo-irradiated TiO ₂ suspensions by chemiluminescence and density functional theory calculations, which made great contribution to photocatalytic reactions, responsible for about 50% of reduction by TiO ₂ .