Photocatalytic Properties and Applications of Titanium Dioxide Systems

Titanium dioxide (TiO₂) has emerged as a cornerstone material in photocatalysis owing to its chemical stability, low cost and non-toxicity. In its most active form, TiO₂ absorbs ultraviolet light to generate electron–hole pairs that drive redox reactions at its surface. The interplay of crystalline phases, most notably anatase and rutile, governs charge separation and recombination rates: mixed-phase systems often outperform single-phase materials through interfacial band alignment. Strategies to extend light absorption into the visible region include non-metal and metal doping, surface functionalisation with dyes or quantum dots, and the construction of heterojunctions with narrow-gap semiconductors. These modifications enhance solar utilisation and suppress recombination, enabling applications ranging from water splitting for hydrogen production to the degradation of organic pollutants and reduction of carbon dioxide. Recent advances have explored nanoscale architectures, such as nanotubes, nanosheets and three-dimensional networks, to maximise active surface area and optimise charge-carrier pathways. The global significance of TiO₂ photocatalysis is evident in its potential for decentralised water treatment, air purification and sustainable fuel generation.

Research from Nature Portfolio

Innovative synthesis of phase-junction TiO₂ below the anatase–rutile transition temperature has demonstrated that tuning the ratio of the two phases directly on titanium substrates can yield intimate solid–solid interfaces, markedly enhancing interparticle charge transfer and photocatalytic degradation rates. A complementary study established the fundamental band alignment between anatase and rutile polymorphs by transient infrared spectroscopy, revealing that dynamical factors such as particle size and surface scavengers dictate the direction of electron migration, thus allowing rational design of mixed-phase catalysts with tailored charge-separation pathways. More recently, two-dimensional heterostructures combining TiO₂ nanosheets with transitional metal sulphide layers have been fabricated via sequential sulphurisation and oxidation, yielding nano-whisker geometries that inhibit phase transition and present high surface crystallinity. These architectures exhibit synergistic light absorption and prolonged charge-carrier lifetimes, underpinning enhanced visible-light activity in pollutant degradation.

Photocatalytic Properties and Applications of Titanium Dioxide Systems publication trend

The graph below shows the total number of articles in photocatalytic properties and applications of titanium dioxide systems across all publications each year (not limited to Nature Index journals).

Technical terms

Photocatalysis: The acceleration of a chemical reaction by a catalyst activated by light.
Anatase and Rutile: Two crystalline polymorphs of TiO₂ that differ in band structure and surface energetics.
Band Gap: Energy difference between the valence band and conduction band; determines light absorption threshold.
Charge Carrier Recombination: Process by which photogenerated electrons and holes recombine, reducing photocatalytic efficiency.
Phase Junction: Interface between different crystalline phases that promotes directional charge separation.
Heterojunction: Junction between two distinct semiconductors, used to enhance charge separation and extend light absorption.

References

1. C-,N- and S-Doped TiO2 Photocatalysts: A Review. Catalysts (2021).
2. Understanding the anatase–rutile phase junction in charge separation and transfer in a TiO 2 electrode for photoelectrochemical water splitting. Chemical Science (2016).
3. Self-induced synthesis of phase-junction TiO2 with a tailored rutile to anatase ratio below phase transition temperature. Scientific Reports (2016).
4. Band Alignment and Controllable Electron Migration between Rutile and Anatase TiO2. Scientific Reports (2015).
5. Enhanced visible-light photocatalytic activity of anatase-rutile mixed-phase nano-size powder given by high-temperature heat treatment. Royal Society Open Science (2020).
6. Evolution of large area TiS2-TiO2 heterostructures and S-doped TiO2 nano-sheets on titanium foils. Scientific Reports (2019).
7. Molecular Adsorption of H2O on TiO2 and TiO2:Y Surfaces. Journal of Human Earth and Future (2022).