Photocatalytic Performance of Quantum Dot/Titanium Dioxide Composites

Composites of quantum dots (QDs) with titanium dioxide (TiO₂) have emerged as a versatile platform to harness solar energy for chemical transformations. By combining the strong oxidising ability of TiO₂ with the size-tuned optical properties of QDs, these hybrids extend light absorption into the visible spectrum and promote efficient separation of photogenerated charge carriers. Strategies such as heterojunction formation, surface doping and morphological control have been shown to suppress electron–hole recombination and enhance interfacial charge transfer. As a result, QD/TiO₂ composites exhibit remarkable activity in applications ranging from the degradation of organic pollutants and pharmaceuticals to photocatalytic water splitting for hydrogen generation and self-cleaning coatings on construction materials. The interplay between QD composition (carbon, graphene or doped semiconductor), TiO₂ crystalline facets and composite architecture underpins both the fundamental understanding and practical deployment of these materials in sustainable energy and environmental technologies.

Research from Nature Portfolio

A pioneering study demonstrated the fabrication of nitrogen-doped carbon quantum dots loaded onto P25 TiO₂ via a simple hydrothermal route. The resultant heterojunction broadened photoresponse into the visible region, accelerated charge transport and significantly improved the photocatalytic decomposition of Rhodamine B, achieving over a tenfold enhancement compared with bare P25. Radical-trapping experiments and electron paramagnetic resonance analyses elucidated the roles of specific reactive species and charge-transfer pathways, offering new insights into the design principles of carbon dot–TiO₂ composites for environmental remediation.

Photocatalytic Performance of Quantum Dot/Titanium Dioxide Composites publication trend

The graph below shows the total number of articles in photocatalytic performance of quantum dot/titanium dioxide composites across all publications each year (not limited to Nature Index journals).

Technical terms

Quantum dot (QD): A semiconductor nanocrystal whose electronic and optical properties are determined by its size and shape, leading to tunable light absorption and emission.

Heterojunction: An interface between two different semiconductors that facilitates directed transfer of electrons and holes, thus reducing recombination and enhancing photocatalytic efficiency.

Electron–hole recombination: The process by which photogenerated electrons and holes reunite, dissipating energy as heat or light and limiting photocatalytic activity.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen (e.g. hydroxyl radicals, superoxide) that mediate the oxidative degradation of organic contaminants.

S-scheme heterojunction: A band alignment in which photogenerated electrons and holes separate along a step-like pathway, combining strong redox potentials with efficient charge separation.

References

1. A solar flow photo-reactor for antibiotic removal from aquaculture effluents using TiO2/carbon quantum dots. Chemosphere (2023).
2. Preparation of the heterojunction catalyst N-doping carbon quantum dots/P25 and its visible light photocatalytic activity. Scientific Reports (2019).
3. Porous TiO2/Carbon Dot Nanoflowers with Enhanced Surface Areas for Improving Photocatalytic Activity. Nanomaterials (2022).
4. Exploring the efficiency of nitrogenated carbon quantum dots/TiO2 S-scheme heterojunction in the photodegredation of ciprofloxacin in aqueous environments. Turkish Journal of Chemistry (2024).