Recent advances in carbon quantum dot photocatalysis

Carbon quantum dots (CQDs), as a novel type of carbon nanomaterial, are widely used in fields such as drug delivery, biosensing, fluorescent probes, and photocatalysis, benefiting from their excellent photostability, water solubility, biocompatibility, fluorescence, low-cost, and green non-toxicity. Meanwhile, due to the conjugated π structure of CQDs and surface defects generated by sp² hybridization, they possess unique optoelectronic properties, including tunable fluorescence, good upconversion photoluminescence, and efficient photoelectron transfer. These properties are key to the role of CQDs in the field of photocatalysis. This review summarises CQDs’ research progress and reaction mechanisms in photocatalysis, including their optical properties and synthesis strategies. Emphasis was placed on the application of CQDs in the field of photocatalysis, including photocatalytic CO₂ conversion, degradation of organic and heavy metal pollutants, hydrogen production, and nitrogen fixation. In addition, the challenges and prospects of CQDs in the field of photocatalysis are discussed, providing new ideas for studying CQDs photocatalytic materials.