One Step Synthesis of Oxygen Defective Bi@Ba2TiO4/BaBi4Ti4O15 Microsheet with Efficient Photocatalytic Activity for NO Removal

Abstract

Photocatalysis is an effective technology for NO removal even at low concentrations in the ambient atmosphere. However, the low efficiency of this advanced process and the tendency of producing toxic byproducts hinder the practical application of photocatalysis. To overcome these problems, the Bi@Ba2TiO4/BaBi4Ti4O15 photocatalytic composites were successfully prepared by a one-step hydrothermal method. The as-synthesized photocatalysts exhibited an efficient photocatalytic performance and generated low amounts of toxic byproducts. X-ray diffraction studies show that Bi3+ is successfully reduced on the surface of Ba2TiO4/BaBi4Ti4O15 (BT/BBT). After L-Ascorbic acid (AA) modification, the photocatalytic NO removal efficiency of Bi@Ba2TiO4/BaBi4Ti4O15 is increased from 25.55% to 67.88%, while the production of the toxic byproduct NO2 is reduced by 92.02%, where the initial concentration of NO is diluted to ca. 800 ppb by the gas stream and the flow rate is controlled at 301.98 mL·min−1 in a 150 mL cylindrical reactor. Furthermore, ambient humidity has little effect on the photocatalytic performance of theBi@Ba2TiO4/BaBi4Ti4O15, and the photocatalyst exhibits excellent reusability after repeated cleaning with deionized water. The improved photocatalytic effect is attributed to the addition of AA in BT/BBT being able to reduce Bi3+ ions to form Bi nanoparticles giving surface plasmon effect (SPR) and generate oxygen vacancies (OVs) at the same time, thereby improving the separation efficiency of photogenerated carriers, enhancing the light absorption, and increasing the specific surface areas. The present work could provide new insights into the design of high-performance photocatalysts and their potential applications in air purification, especially for NO removal.