Nitrogen doping in coexposed (001)-(101) anatase TiO₂ surfaces: a DFT study

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Recent experiments highlight the high photocatalytic activity of coexposed anatase (001)-(101) titanium dioxide (TiO2) surfaces.
• Nitrogen (N)-doping is a promising strategy to enhance photocatalyst performance, particularly under visible light irradiation.

Purpose of the Study:

• To investigate the impact of N-doping on the structural and electronic properties of coexposed anatase (001)-(101) TiO2 surfaces.
• To understand how N-doping influences the material's interaction with light and its photocatalytic potential.

Main Methods:

• Utilizing Density Functional Theory (DFT) calculations to model N-doped TiO2 surfaces.
• Analyzing dopant segregation, electronic band structure, and defect stabilization.

Main Results:

• N-doping shows a tendency for dopant segregation at the interface at low concentrations, with bulk doping occurring at higher concentrations.
• N-doping does not alter the band alignment between the (001) and (101) facets, maintaining their respective roles in charge carrier stabilization.
• Visible light absorption is significantly enhanced due to the formation of N-induced gap states and the stabilization of oxygen vacancies.

Conclusions:

• N-doping effectively improves the visible light absorption capabilities of anatase (001)-(101) TiO2.
• The stabilization of oxygen vacancies by N-doping further contributes to enhanced light absorption, making these materials more suitable for photocatalysis.