Double internal magnetic fields significantly improve photocatalytic activity over Ba0.5Sr0.5TiO3/BaFe12O19/SrFe12O19 photocatalysts

Abstract

The Z-scheme Ba 0.5 Sr 0.5 TiO 3 /BaFe 12 O 19 /SrFe 12 O 19 (BST5/10 %BFO/SFO) magnetic photocatalysts with different SFO mass percents and bimagnetic components were successfully constructed using the multistep polyacrylamide gel method and heat treatment technology. The phase structure information, binding energy information, microstructure information, optical and magnetic properties and photocatalytic activity of BST5/10 %BFO/SFO photocatalysts were confirmed by various characterization methods. The photocatalyst composed of BST5, BFO, and SFO is completely free of impurities and creates a unique interface contact between its components. When the mass percentage of SFO was 20 wt%, the BST5/10 % BFO/SFO photocatalyst exhibited the highest saturation magnetization , remanent magnetization , high optical absorption coefficient and photocatalytic activity for the degradation of tetracycline hydrochloride (TC). When the optimal catalyst content is 1 g/L, the initial TC concentration is 100 mg/L and pH is 13, the degradation percentage of BST5/10 % BFO/SFO photocatalyst reaches 87 %. Through active species verification experiments, it was found that the holes, hydroxyl radicals , and superoxide radicals were the most dominant active species in the TC degradation process of BST5/10 % BFO/SFO photocatalysts. The transfer and separation efficiency of charge carriers is enhanced and the formation of Z-scheme heterojunctions is facilitated by the bimagnetic components in BST5/10 % BFO/SFO photocatalysts, which improve the photocatalytic activity of the system. A new technical reference and concept for designing new magnetic separation photocatalysts can be found in the construction method of Z-scheme heterojunction caused by bi-magnetic components. The multistep polyacrylamide gel method and heat treatment technology has been developed for fabrication of Ba 0.5 Sr 0.5 TiO 3 /BaFe 12 O 19 /SrFe 12 O 19 magnetic photocatalysts. The bimagnetic components acting as electron emitters in Ba 0.5 Sr 0.5 TiO 3 /BaFe 12 O 19 /SrFe 12 O 19 photocatalysts promote the formation of Z-scheme heterojunction and enhance the transfer and separation efficiency of charge carriers, thus improving the photocatalytic activity of the system. • A facile method has been used to synthesize the BST5/10 %BFO/SFO photocatalysts. • The BST5/10 %BFO/SFO photocatalysts exhibit high photocatalytic activity. • The bimagnetic components act as electron emitters to enhance the photocatalytic activity of the system. • Z-scheme photocatalytic mechanism of BST5/10 %BFO/SFO photocatalysts was proposed.