One-pot preparation of AgBr/α-Ag2WO4 composite with superior photocatalytic activity under visible-light irradiation

Recently, semiconductor photocatalysts have received much attention in the field of eliminating organic pollutants in waste-water without causing any new accompanied secondary pollution. Herein, we have reported a new visible-light-driven photocatalyst of AgBr/alpha-Ag2WO4 composites with high efficiency of pollution elimination. A series of composites were prepared with addition of various amounts of cetyltrimethylammonium bromide (CTAB, from 0.1-2.0 m moL) to the Ag2WO4 precipate-containing solution via a facile one-pot hydrothermal route. The as-prepared composites were characterized by various techniques like powder XRD, UV-vis DRS, SEM, element mapping, HR-TEM, XPS and PL analyses. Photo-catalytic behaviors of these AgBr/alpha-Ag2WO4 composites were examined through the removal of Rhodamine B (RhB) under visible-light radiation. It is confirmed that the AgBr/alpha-Ag2WO4 composites show the higher photocatalytic ability than pure AgBr and alpha-Ag2WO4 samples. Particularly, the AgBr/alpha-Ag2WO4 composite obtained with the addition of 1.0 m moL of CTAB possesses 100% degradation of RhB in 60 min and an outstanding photostability. The enhanced photocatalytic activity of the AgBr/alpha-Ag2WO4 composite is mainly attributed to the creation of heterojunction on the interface between AgBr and alpha-Ag2WO4, which can efficiently facilitate the rapid charge separation and recombination reduction of the photo-created electron-holes pairs. A photo-degradation mechanism of AgBr/alpha-Ag2WO4 composite is also discussed based on the band position and radical trapping tests. As a result, the as-prepared AgBr/alpha-Ag2WO4 composite is proved to be a promising candidate of photocatalyst for the treatment of wastewater.