Linking the enhanced deep NO oxidation of a ferroelectric KBiTiO nanowire photocatalyst to its spontaneous polarization and oxygen vacancies

Fast recombination and slow transfer of photogenerated charge carriers impede the photo-oxidation process of NO x . Herein, the K 0.5 Bi 0.5 TiO 3 with oxygen vacancies (KBT-O) realized the enhancement of charge separation caused by the effect of spontaneous polarization. In addition to spontaneous polarization, oxygen vacancies introduced intentionally under UV light irradiation act as hubs for capturing the photogenerated electrons to further enhance the separation of charge carriers due to a surface local electric field. Oxygen vacancies can also serve as active sites to enhance the adsorption of NO and O 2 . In particular, the built-in electric field in the KBT-O because of spontaneous polarization improves the separation efficiency of photogenerated charge carriers, resulting in an increased removal rate of NO (53.6%) and a reduced concentration of formed NO 2 (2.1 ppb). This work unravels the important role of spontaneous polarization along with oxygen vacancies in enhancing the deep oxidation of NO over ferroelectric KBT-O photocatalyst under visible light irradiation. The mechanism of NO x photo-oxidation and the pathway of photogenerated charge carries mechanism over K 0.5 Bi 0.5 TiO 3 photocatalyst.