  Two-dimensional transition metal dichalcogenides (MX2)/metal oxide
heterostructures have shown unique physical properties, making them promising
materials for various applications ranging from photocatalysis to solar energy
conversion. Understanding the interfacial interactions is highly desirable for
designing these heterostructures having excellent performance. Here we
systematically study the interfacial interaction in monolayer MX2 (M=Mo, W;
X=S, Se)/CeO2 heterostructures and its effects on electronic and optical
properties by density functional theory. It is found that the interfacial
interaction in the MX2/CeO2 depends predominantly on the chalcogen (X) element.
Particularly, the band gap variation and important electronic states at
conduction band minimum or valence band maximum of the heterostructures are
determined by the strength of interfacial interaction. The MX2/CeO2
heterostructures with the same chalcogen (X) element have similar absorption
spectra from ultraviolet to near-infrared regions. These results suggest that
the chalcogen (X) element is a key factor in tuning the properties of MX2/metal
oxide heterostructures.
