Electrospun Bi-decorated BixTiyOz/TiO2 flexible carbon nanofibers and their applications on degradating of organic pollutants under solar radiation

Abstract

Presently, photocatalytic degradation has emerged as an attractive and efficient technology for wastewater treatment. In order to avoid hurdles, such as difficulty in the suspended photocatalyst segregation from the aqueous system and low reutilization rate, the strategy of immobilizing photocatalysts with electrospun fibers has been widely studied. However, those methods usually require multi-step preparation and complex operations. Considering this, a novel metallic Bi-decorated flexible multiphase BixTiyOz/TiO2 electrospun carbon nanofibers (Bi/BixTiyOz-TiO2/CNFs) with high photocatalytic efficiency, good mechanical property, good stability, easy separation, and recovery were synthesized via a one-step approach of pre-oxidation and carbonization treatment. The as-prepared Bi/BixTiyOz-TiO2/CNFs with multiphase BixTiyOz, anatase TiO2, and metallic Bi particles embedded not only enhance the harvest of light but also provide more separation paths for photogenerated carriers, which improve photocatalytic efficiency greatly. The Bi/BixTiyOz-TiO2/CNFs (S3) exhibited excellent photocatalytic performance and the degradation rate of 10 mg L–1 Rhodamine B (RhB) was up to 97% in only 30 min under simulated sunlight irradiation. Also, S3 exhibited stable activity during 5 cycles of experiments since the degradation rates remained at about 97% in 30 min. The mechanism of degradation of RhB by Bi/BixTiyOz-TiO2/CNFs in the photocatalytic process was also proposed based on active species trapping experiments. The work in this paper shows that Bi/BixTiyOz-TiO2/CNFs are easy to prepare and have high photocatalytic ability and stability, thereby offering a new strategy in catalyst immobilization and wastewater treatment.