A novel 0D/2D heterojunction Bi2Sn2O7/BiOCOOH with BiOCOOH nanosheets as support for the boosted photodegradation of tetracycline: The role of BiOCOOH in the photogenerated electron transfer

Developing efficient photocatalysts and eliminating emerging contaminants are the research hotspots in the field of environment. Herein, a novel heterojunction photocatalyst Bi2Sn2O7/BiOCOOH was constructed by integrating the merits of both narrow bandgap and wide bandgap semiconductors. The synthesized Bi2Sn2O7/BiO- COOH was characterized in detail using various methods. The photocatalytic activity of Bi2Sn2O7/BiOCOOH toward tetracycline (TC) was investigated. Bi2Sn2O7/BiOCOOH possesses a high visible light response. The formation of the unique 0D/2D heterojunction interface between Bi2Sn2O7 and BiOCOOH as well as the formation of the internal electric field greatly accelerate the migration of the photoinduced electrons from Bi2Sn2O7 to BiOCOOH. Because of the well-matched band alignment of Bi2Sn2O7 and BiOCOOH, center dot O2- , h+, and center dot OH all serve as active species that participate in TC photodegradation. Compared to Bi2Sn2O7, the heterostructure Bi2Sn2O7/ BiOCOOH presents dramatically enhanced photocatalytic activity toward TC, and the photodegradation rate of TC reaches up to 90 %. The reaction rate constant (0.0372 min-1) of TC by Bi2Sn2O7/BiOCOOH is 4.4 times that of pure Bi2Sn2O7. In addition, Bi2Sn2O7/BiOCOOH exhibits good stability. The environmental factors exert a slight influence on TC degradation. Bi2Sn2O7/BiOCOOH is a promising photocatalyst for environmental remediation. The present work offers a new idea for the development of efficient composite photocatalysts.