First-principles study on transition metal-doped anatase TiO2

Area of Science:

• Materials Science
• Solid State Physics
• Computational Chemistry

Background:

• Anatase titanium dioxide (TiO2) is a widely studied photocatalyst.
• Enhancing TiO2's visible light response and photoreactivity is crucial for practical applications.
• Transition metal doping is a promising strategy to modify TiO2's electronic and optical properties.

Purpose of the Study:

• To investigate the effects of transition metal doping on the electronic structures, formation energies, and band edge positions of anatase TiO2.
• To understand how doping influences the photocatalytic properties and stability of TiO2.
• To provide theoretical guidance for designing novel TiO2-based photocatalysts.

Main Methods:

• Ab initio band calculations using density functional theory (DFT).
• Planewave ultrasoft pseudopotential method.
• Modeling of transition metal-doped TiO2 using supercells (24-atom 2×1×1) with one Ti atom substituted by a transition metal.

Main Results:

• Most transition metal dopants narrow the band gap of TiO2, enhancing photoreactivity.
• Doping maintains the strong redox potential of TiO2.
• Co-, Cr-, and Ni-doped TiO2 exhibit negative impurity formation energies under O-rich conditions, indicating experimental ease of preparation and good stability.
• Calculations predict improved visible light response for doped TiO2.

Conclusions:

• Transition metal doping is an effective strategy to improve the visible light photocatalytic activity of anatase TiO2.
• The theoretical findings suggest that Co-, Cr-, and Ni-doped TiO2 are promising candidates for stable and highly active photocatalysts.
• This research provides valuable theoretical insights for the rational design of advanced photocatalytic materials.