Enhanced piezocatalytic activity of BiFeO3 hollow spheres with surface iodine-grafting

The insufficient active sites, low separation efficiency of free carriers and poor capacity to generate active free radicals are limitations of asymmetrical BiFeO 3 in piezocatalysis. To address these issues, BiFeO 3 hollow nanospheres with exposed abundant catalytic active sites were fabricated via a solvothermal method for the first time. In addition, surface iodine-grafting was introduced, resulting in a local electric field and the conduction band potential of BiFeO 3 closer to the O 2 /·O 2 – redox potential (-0.33 eV). It facilitated charge transmission and active species generation to remove bisphenol A under ultrasonic vibration. Thus, the iodine-grafted BiFeO 3 hollow nanospheres could completely degrade 20 mL bisphenol A (10 ppm) within 60 min with a relatively fast rate constant of 0.153 min −1 , which was 4.5 times higher than that of un-grafted BiFeO 3 . This work provides a feasible approach to construct efficient piezocatalysts for industrial wastewater purification.