N2O decomposition on TiO2 (110) from dynamic first-principles calculations

Area of Science:

• Surface science
• Materials chemistry
• Computational chemistry

Background:

• Investigated nitrous oxide (N2O) dissociation on titanium dioxide (TiO2) (110) surfaces using density-functional theory (DFT).
• Employed static and dynamic calculations to understand N2O decomposition mechanisms.
• Determined that N2O dissociation is unfavorable on stoichiometric TiO2 surfaces.

Discussion:

• Oxygen bridging vacancies on TiO2 (110) enable N2O decomposition by providing electrons to the adsorbed molecule.
• Identified two distinct decomposition pathways based on molecular adsorption orientation relative to the vacancy.
• Analyzed the energetic favorability and reaction barriers for each pathway.

Key Insights:

• N2O decomposition occurs spontaneously and energetically downhill when the oxygen end adsorbs on a vacancy, leading to N2 release and vacancy oxidation.
• An alternative pathway involves an intermediate bridging configuration, requiring a small energy barrier, resulting in N2 gas and surface oxygen adatoms.
• The study provides a detailed atomistic understanding of N2O decomposition on defective TiO2 surfaces.

Outlook:

• Results offer insights into N2O abatement strategies on TiO2-based catalysts.
• Connects theoretical findings with recent experimental observations in N2O decomposition studies.
• Suggests potential for engineered TiO2 surfaces with controlled vacancies for enhanced catalytic activity.