| 초록 |
Semiconductor photocatalysis, which can actively affect molecular reaction through converted photon energy, has been recognized as a promising method for environmental remediation due to versatile, sustainable, and eco-friendly technology. The ultimate goal of this technology is to completely eliminate various harmful substances in the air or aqueous solution using solar energy and photocatalyst, in order to achieve this goal, two main challenges, high quantum efficiency and absorption capacity, have remained. Recently, the black metal oxide, contained oxygen defect or high valence state metal ion, has been proved the effective approach to increase absorption capacity by decreasing their optical band gap. Therefore, several studies have been conducted using a black metal oxide due to its superior properties, but only limited semiconductor materials such as TiO2, ZnO, and ZrO2 have been conducted. Among traditionally studied photocatalysts, ferroelectric perovskite photocatalysts have been received a lot of interest owing to effective charge separation ascribed to ferroelectricity, particularly, barium titanate (BaTiO3) is one of the promising candidates as photocatalyst due to their deep band edge position. However, they are inherently limited as photocatalyst by the weak solar absorption resulted from a large bandgap of 3.3 eV. Although, hydrogenated black BaTiO3 were reported to solve this intrinsic problem, studies on the correlation between the physicochemical properties and photocatalytic activities according to oxygen vacancies are insufficient. In this study, the BaTiO3 nanoparticles with controlled oxygen vacancies contents were successfully synthesized by a facile ultrasonic-assisted solid reaction and sequent calcination process. Black TiO2 nanoparticles were used as the Ti source to efficiently introduce oxygen vacancies in final BaTiO3 nanoparticles, and the black TiO2/BaCO3 mixture was calcined in different atmospheres to control the amount of oxygen vacancies. Then, the variation on the physicochemical properties of BaTiO3 with a detailed study on the correlation between oxygen vacancy contents and photocatalytic activities was systematically investigated. |
