Selenium-modified TiO2 and its impact on photocatalysis.

Area of Science:

• Materials Science
• Photocatalysis
• Environmental Chemistry

Background:

• Titanium dioxide (TiO2) is a widely studied photocatalyst, but its application is limited by its wide bandgap, restricting its activity to UV light.
• Developing visible-light-responsive photocatalysts is crucial for efficient solar energy utilization and environmental remediation.
• Selenium modification offers a potential strategy to enhance TiO2's photocatalytic properties.

Purpose of the Study:

• To synthesize and characterize selenium-modified titanium dioxide (Se-TiO2).
• To evaluate the photocatalytic activity of Se-TiO2 under UV and visible light.
• To investigate the mechanism of photocatalysis, including electron trapping and reactive species generation.

Main Methods:

• Synthesis of Se-TiO2 via a preparation method.
• Characterization using X-ray photoelectron spectroscopy (XPS).
• Photocatalytic degradation experiments using quinoline and other organic molecules under UV and visible light (>435 nm).

Main Results:

• Se-TiO2 exhibited enhanced visible light absorption compared to undoped TiO2.
• Se-TiO2 demonstrated photocatalytic degradation of quinoline under UV light, at a slightly faster rate than undoped TiO2.
• Se-TiO2 effectively degraded organic molecules under visible light through a single electron transfer pathway.
• XPS analysis confirmed that Se atoms in Se-TiO2 trap photogenerated electrons, especially under hypoxic conditions.

Conclusions:

• Selenium modification enhances the visible light absorption and photocatalytic performance of TiO2.
• Se-TiO2 utilizes a single electron transfer pathway for visible light photocatalysis.
• The selenium component plays a critical role in electron trapping, improving photocatalytic efficiency.