Facile construction of novel BiOBr/Bi12O17Cl2 heterojunction composites with enhanced photocatalytic performance

Abstract A family of novel heterostructured 2D/2D BiOBr/Bi12O17Cl2 photocatalysts were fabricated through a facile in situ chemical deposition-precipitation method, characterized using a suite of solid characterization tools, and examined for the degradation of multiple representative waterborne pollutants. The BiOBr/Bi12O17Cl2 composites significantly accelerated the photocatalytic degradation of 4-chlorophenol under simulated sunlight irradiation, and the 100%-BiOBr/Bi12O17Cl2 increased the degradation rate of 4-chlorophenol by 3.2 and 4.1 times in comparison with pristine BiOBr and Bi12O17Cl2, respectively. Additionally, the BiOBr/Bi12O17Cl2 composites displayed superior performance for the degradation of methyl orange and tetracycline under visible light irradiation. The enhanced photocatalytic activity of BiOBr/Bi12O17Cl2 composites is likely attributed to the synergistic effects between BiOBr and Bi12O17Cl2, such as increased surface area, improved light harvesting ability, and most importantly, enhanced separation efficiency of photoinduced charge carriers because of the formation of heterojunctional interfaces between BiOBr and Bi12O17Cl2. Trapping experiments revealed that superoxide anions and holes were the main reactive species responsible for the degradation of waterborne pollutants. A possible photocatalytic mechanism was proposed based on the observed experimental results. The present work provides insights into design and application of novel, highly efficient and stable bismuth-based photocatalysts for water treatment and purification.