  This study investigates the catalytic degradation of ground-level ozone on
low-index stoichiometric and reduced CeO$_2$ surfaces using first-principles
calculations. The presence of oxygen vacancies on the surface enhances the
interaction between ozone and catalyst by serving as active sites for
adsorption and decomposition. Our results suggest that the {111} surface has
superior ozone decomposition performance due to unstable oxygen species
resulting from reaction with catalysts. However, when water is present, it
competes with ozone molecules for these active sites, resulting in reduced
catalytic activity or water poisoning. A possible solution could be heat
treatment that reduces the vacancy concentration, thereby increasing the
available adsorption sites for ozone molecules while minimizing competitive
adsorption by water molecules. These results suggest that controlling moisture
content during operation is crucial for the efficient use of CeO$_2$-based
catalysts in industrial applications to reduce ground-level ozone pollution.
