Effect of lattice strain on the oxygen vacancy formation and hydrogen adsorption at CeO₂(111) surface

Using first-principles calculation, the effect of lattice strain on the oxygen vacancy formation at CeO₂(111) surface has been investigated. The tensile strain facilitates the oxygen vacancy formation at the surface and the compressive strain hinders the process. This is in part due to the strengthening or weakening of the surface Ce–O bond under the lattice strain. On the other hand, a more open surface with a larger lattice constant can better accommodate the larger Ce³⁺ and thus facilitate the structural relaxation of the reduced surface. The studies on the strain effect on the atomic hydrogen adsorption at the defect-free CeO₂(111) surface show that the adsorption strength monotonously increases with the increase of the lattice strain, further confirming the tunable surface chemical activity by lattice strain. - Highlights: • Tensile (compressive) strain makes the formation of the OV at the CeO₂(111) surface easier (harder). • Tensile strain weakens the surface Ce–O bond and compressive strain strengthens the surface Ce–O bond. • The larger lattice constant can give more space for Ce³⁺ and facilitate the relaxation of the reduced surface. • The interaction strength between the atomic H and CeO₂(111) surface increases with the expansion of the lattice