First-principles investigation on the structural, elastic and electronic properties and mechanism on the photocatalytic properties for SrNbO3 and Sr0.97NbO3

The structural, elastic and electronic properties of perfect SrNbO3 and defective Sr0.97NbO3 are investigated by employing the plane-wave pseudopotentials methods based on density functional theory (DFT). The photocatalytic activity is also discussed for both systems based on the obtained electronic structures. The single-crystal elastic constants, polycrystalline elastic modulus, Poisson's ratio and anisotropy factors are obtained from the Voigt-Reuss-Hill approximations. Further, the elastic anisotropy is discussed and visualized in the light of the elastic properties. The direction dependence of Young's modulus is also compared for the two systems. The Fermi levels going through the conduction bands indicate metallic nature of SrNbO3 and Sr0.97NbO3. The transitions from CB to B band can yield visible light absorption. From the effects of the electronic and crystallographic structures on photocatalytic activity, perfect SrNbO3 can show higher photocatalytic activity than defective Sr0.97NbO3. The related physical properties of defective Sr0.97NbO3 are predicted for the first time. The present study would contribute to the further researches on the photocatalytic properties of SrNbO3 based systems.