Ferroelectricity enhanced photocatalysis in Bi2WO6 ultra-thin nanosheets

The fast recombination of photo-induced electrons and holes have long been an obstacle in hampering the photocatalytic reaction rate. To mediate this issue, various modulation methods have been explored, including rare metal doping, morphology control and heterojunction construction. However, these methods can only facilitate the surface charge transfer. In recent years, internal electric field modulation has been attracting more and more attention, due to its utility in promoting the bulk charge separation and transportation. Semiconductors with ferroelectricity, which can build directional internal field, is believed to possess enhanced photocatalysis efficiency. In this study, Bi2WO6 (BWO) ultra-thin nanosheets with ferroelectricity have been synthesized through hydrothermal process. The morphology and size can be controlled via surfactant addition. After corona poling, the ferroelectric field can be further enhanced, providing more efficient facilitation of carrier separation and higher reaction efficiency. The photodegradation efficiency toward Rhodamine B (RhB) and methyl orange (MO) are tested, and the polarized BWO-30 and BWO-40 can reach a 100 % degradation of RhB in 5 min, which is significantly faster than origin samples, and superior to most non-precious metal catalysts. This work proves the applicable of ferroelectric enhancement in BWO nanosheets, providing novel tactic for future catalysts design.