Direct Z-scheme Bi2S3/BiFeO3 heterojunction nanofibers with enhanced photocatalytic activity

Reasonable design of heterojunctions is considered to be an effective way to construct highly efficient photocatalysts. In this work, Bi2S3/BiFeO3 heterojunction nanofibers with tightly integrated interface were prepared by electrospinning technique and in-situ anion exchange method. Various characterizations were conducted to analyze the structure and morphology of Bi2S3/BiFeO3 composites. The photocatalytic activities of the obtained Bi2S3/BiFeO3 heterojunctions were evaluated by photodegradation of tetracycline hydrochloride (TC) under visible light irradiation. It can be found that Bi2S3/BiFeO3 heterojunctions showed enhanced photocatalytic degradation performance, and their photocatalytic activities can be easily optimized by changing the amount of thioacetamide (TAA). When the amount of TAA was 0.1 mmol, the obtained Bi2S3/BiFeO3 (TAA-2) sample exhibited the best photocatalytic performance, which was 5 and 6 times of pure BiFeO3 and Bi2S3, respectively. Besides, the photocatalytic mechanism was systematically studied by monitoring the active species and radicals, and by performing the optical and photoelectrochemical tests. Accordingly, a direct Z-scheme charge migration mechanism for Bi2S3/BiFeO3 heterojunctions was proposed. The enhanced photocatalytic performance of Bi2S3/BiFeO3 heterojunctions can be attributed to the improved visible light response and efficient charge separation and transfer.