Self-assembly of PDINH/TiO2/Bi2WO6 nanocomposites for improved photocatalytic activity based on a rapid electron transfer channel

Abstract

An organic-inorganic nanosheet photocatalyst PDINH/TiO2/Bi2WO6(P/T/B) is prepared by self-assembly of TiO2 and Bi2WO6 on 3,4,9,10-tetracarbonate diimide (PDINH). PDINH monolayers self-assemble into organic supramolecular carriers at approximately 200 nm under π-π stacking. After sulfuric acid pretreatment, –OH is introduced into the TiO2 crystal, and then ultrasonic dispersion facilitates its efficient interaction with -C = O bond on the PDINH to form hydrogen-like bond –CO···H. In the hydrothermal reaction, Bi2WO6 is acidified by mixed acid and assembled on the surface of PDINH by intermolecular force. Therefore, both TiO2 and Bi2WO6 can be uniformly supported on the surface of PDINH to form flake photocatalyst. A good matching between PDINH and Bi2WO6 provides a fast electron transfer channel and accelerates the transfer rate of photogenerated carriers between TiO2 and Bi2WO6. In the photocatalytic process of P/T/B, electrons are enriched in the top band of TiO2, and the holes are retained in the bottom band of Bi2WO6, which greatly improves the transfer rate of photogenerated carriers between TiO2 and Bi2WO6 and enhances the degradation ability of organic pollutants. The degradation rate of phenol can reach 98% in 300 min, which is three higher than that of TiO2 and much higher than that of Bi2WO6.