A novel Bi2WO6/DMPBP[5] composite for cyclic adsorption and photocatalytic degradation of organic pollutant in water

Abstract

The typical photocatalyst Bi2WO6（BWO）has low energy efficiency due to its low specific surface area (SSA) and high photogenerated electron/hole recombination rate. In this study, a three-dimensional spherical BWO/DMPBP[5] composite was synthesized by loading DMpillar[5]arene-based porous polymer (DMPBP[5]) on BWO through hydrothermal method to correct these deficiencies. Scanning electron microscopy and transmission electron microscopy showed that the modified BWO transformed into three-dimensional spherical composite. Furthermore, BET surface area analysis further proved that compared with the original photocatalyst BWO whose SSA is 19 m2·g−1, the optimized composite BWO-7% exposes more SSA with a value of 134 m2·g−1, endowing it more adsorption and photocatalytic active sites. Results showed that photocatalytic reaction rate constants of BWO-7% increased by more than 10 times, compared with that of BWO. This significant improvement was due to the introduction of DMPBP[5], which could concentrate organic pollutants, thus reduce the distance between contaminants and the active site. More importantly, after DMPBP[5] was loaded, BWO/W5O14 heterojunction was formed. In the detection process, we found that oxygen vacancy was introduced in it, which was more conducive to the separation of electron/hole pairs and improved the photocatalytic performance of visible light. In addition, the adaptability to inorganic salts, pH and recycling performance of BWO composites were excellent. Altogether, this study provides the possibility for the application of new adsorption-photodegradation materials in photocatalytic water treatment.