Density functional theory (DFT) study of the interaction of ammonia with pure and tungsten-doped ceria

Our calculations show that ammonia binds to ceria at the Lewis and Brønsted acid sites, however this binding is very weak (<5 kcal/mol). In the presence of tungsten, the binding to the Lewis acid sites continues to be weak, while the binding to the Brønsted acid sites is increased significantly (to ∼10 kcal/mol). We have used the H-terminated surface to study the Brønsted acidity and as a corollary, we also report the significantly different binding of hydrogen to the pure and tungsten-doped ceria surfaces.