Density functional theory study on the electronic and photocatalytic properties of different phases for Ba₂BiTaO₆

To study the capacity of materials to degrade organic pollutants, the corresponding key factors for three phases of Ba₂BiTaO₆ were performed by first-principles calculations. To ensure the accurate description for electronic properties, GGA and HSE06 were employed to do corresponding calculations and the results verify the higher precision of HSE06. Thereby, following properties are all performed by HSE06. It can be noticed that these three phases are mainly utilizing UV light and show the high efficiency in UV region due to the wide band gaps. Monoclinic phase is favorable for forming the photo-generated electron-hole pairs, which can be attributed to the smallest band gap. Compared with TiO₂ and high efficient perovskite photocatalysts, the lower effective masses of electron for these phases suggest the stronger capacity to transfer charge to surface, indicating the higher photocatalytic activity. Therein, monoclinic phase owns the greatest and weakest capacity for carrier transfer and segregation, respectively. Redox potentials show the high efficiency in photocatalytic generation and degrading organic pollutants for these phases and the defect of insufficient utilization of light can be solved by adopting some methods to further promote their photocatalytic applications.