Efficient Photocatalysis on BaBiO₃ Driven by Visible Light

A novel photocatalyst BaBiO 3 with perovskite structure was prepared by a soft chemical method and characterized by XRD, UV−visible diffuse reflectance spectroscopy, BET surface area measurement, and field emission scanning electron microscopy. The material can absorb light with wavelength λ < 650 nm, which almost covers the region from UV through all strong visible light in the sunlight and an indoor lamp's illumination. It was found that the oxide can efficiently decompose organic contaminants, such as acetaldehyde and methylene blue dye, and yield high photocurrent density whenever under UV-light or visible-light irradiation. The density of states and band edge of the material were theoretically calculated on the basis of density functional theory and an atom's Mulliken electronegativity, respectively. It is revealed that both the valence band and conduction band of BaBiO 3 contain a large portion of Bi 6s orbitals, which results in the narrow band gap, highly mobile charge carriers, and low barrier for photoelectron excitation.