Density functional theory study of rutile VO2 surfaces

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Vanadium dioxide (VO2) exhibits a phase transition near room temperature, making it technologically relevant.
• Understanding the surface properties of VO2 is crucial for optimizing its performance in various applications.

Purpose of the Study:

• To investigate the surface energies and morphology of rutile-like vanadium dioxide (VO2(R)) using density functional theory.
• To explore the redox properties and surface stability of VO2(R) under different oxygen chemical potentials.

Main Methods:

• Density functional theory (DFT) calculations.
• Surface energy calculations for low Miller index planes.
• Analysis of non-stoichiometric surface compositions and their relation to oxygen chemical potential.

Main Results:

• The (110) plane was identified as the most stable surface orientation for VO2(R).
• The equilibrium morphology of VO2(R) particles is acicular, with (110) and (011) planes defining its shape.
• The VO2(110) surface is found to be oxidized even under reducing conditions, favoring surface vanadyl species over peroxo species.

Conclusions:

• The (110) surface plays a critical role in the morphology and stability of vanadium dioxide.
• Surface oxidation of VO2 is prevalent and influenced by oxygen chemical potential, impacting its reactivity.