Water Multilayers on TiO₂ (101) Anatase Surface: Assessment of a DFTB-Based Method

Area of Science:

• Computational materials science
• Surface chemistry
• Quantum chemistry

Background:

• Understanding solid-liquid interfaces is crucial for catalysis and materials design.
• Titania (TiO2) is a widely used material in photocatalysis and environmental applications.
• Accurate modeling of water-TiO2 interfaces is computationally demanding.

Purpose of the Study:

• To assess and improve the accuracy of the self-consistent-charge density functional tight-binding theory (SCC-DFTB) method for water/(101) anatase TiO2 interfaces.
• To develop a computationally efficient yet reliable method for simulating these systems.

Main Methods:

• Density Functional Theory (DFT)-based SCC-DFTB calculations were employed.
• SCC-DFTB parameters for Ti-containing compounds were optimized.
• A modified hydrogen-bond-damping (HBD) function was introduced to improve water energetics.
• Born-Oppenheimer molecular dynamics (MD) simulations were performed.

Main Results:

• The SCC-DFTB+HBD method achieved excellent agreement with DFT-GGA and experimental data for structural and energetic properties.
• MD simulations showed similar water ordering and energetics compared to DFT-GGA.
• The energy barrier for water dissociation on the anatase (101) surface was evaluated.

Conclusions:

• The SCC-DFTB+HBD method provides a highly accurate and computationally efficient description of the water/titania interface.
• This approach enables future studies on larger, more realistic TiO2/liquid water systems.
• The findings are relevant for advancing applications in photocatalysis and materials science.