Pyro-photo-electric catalysis in Bi2WO6 nanostructures for efficient degradation of dyes under thermal-assisted visible light irradiation

Abstract The severe recombination of photo-generated carriers is a key issue that restricts the development of photo-electric catalysis technology. Herein, it is proposed for the first time to utilize the polarization field of Bi2WO6 pyroelectric materials to adjust the photo-electric catalysis performance to achieve the degradation of dyes such as methylene blue (MB) and rhodamine B (RhB). Under 20~45 °C alternating hot and cold, light illumination and external bias, the catalytic rate of Bi2WO6 for MB is 3.06×10-2 min-1 which respectively increases by 2.14 and 13.85 times compared with photo-electric catalysis (9.731×10-3 min-1) and pyro-electric catalysis (2.06×10-3 min-1), and the catalytic rate of Bi2WO6 for RhB is 1.96×10-2 min-1 which respectively increases by 1.04 and 11.35 times compared with photo-electric catalysis (9.60×10-3 min-1) and pyro-electric catalysis (1.59×10-3 min-1). The improvement in catalysis efficiency is originated from the increased carrier concentration caused by the combination of pyro-generated carriers and photo-generated carriers, and the polarized built-in electric field. This study proves that Bi2WO6 pyroelectric materials can be used for photo-electric catalysis degradation of pollutants by utilization of a variety of clean energy including solar energy, thermal energy and electrical energy simultaneously, which provides a critical idea for the design of new environmentally friendly electrodes for catalytic degradation.