Topotactic transformed face-to-face heterojunction of BiOCl/Bi2WO6 for improved tetracycline photodegradation

Heterojunction engineering, especially face-to-face heterojunction, is considered as a serviceable approach to manipulate the activity of photocatalysts. Herein, a face-to-face heterojunction of BiOCl/Bi2WO6 was fabricated by a simple in situ topotactic transformation process. By using BiOCl sheets as building block, a close and face-contact BiOCl/Bi2WO6 heterointerface was obtained because Bi2WO6 sheets were generated on the surface of BiOCl sheets through metathesis Cl- with WO42-. The obtained heterojunctions were characterized by various methods to identify the successful preparation and characteristics. The photocatalytic activities of BiOCl/Bi2WO6 heterojunctions were investigated under visible light irradiation by degradation of tetracycline hydrochloride aqueous solution. The experimental results suggested that BiOCl/Bi2WO6 heterojunctions exhibit significant enhanced efficiency for tetracycline hydrochloride degradation compared with pure BiOCl. The enhanced activity can be attributed to the efficient carrier separation and transfer benefiting from lots of carrier transfer channels in heterointerface and extended visible light harvesting ability of Bi2WO6. The work highlights that the fabrication of heterojunctions by constructing close and large-area contact heterointerface is beneficial to enhance the pollutant degradation activity.