Visible-light photocatalytic activity and mechanism of novel AgBr/BiOBr prepared by deposition-precipitation

Abstract

A new composite photocatalyst AgBr/BiOBr was prepared by loading AgBr on a BiOBr substrate via deposition-precipitation and characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy. The as-prepared AgBr/BiOBr comprised face-centered cubic AgBr and tetragonal BiOBr particles. The average crystalline sizes of AgBr in the AgBr/BiOBr composites were less than 28.5 nm. The absorption edges of AgBr/ BiOBr in visible-light region had a red shift with increasing AgBr content. Photocatalytic degradation of methyl orange results show that the AgBr/BiOBr composites could degrade methyl orange efficiently under visible-light irradiation (>420 nm). The optimal molar percentage of AgBr was 50 mol% with corresponding maximum k app of 0.00619 min 1 . Active ·O 2  played a major role for methyl orange degradation while h + and ·OH had little effect on the photocatalytic process. The enhancement of photocatalytic activity of AgBr/BiOBr is mainly ascribed to the heterojunction effect between AgBr and BiOBr. [28] and WO 3 /BiOCl [29]. The synthesis of BiOX-based composites is very important for the development of highly efficient visible light photocatalysts.AgBr is an important semiconductor widely used as a photosensitive material in photography and as a photocatalyst for the degradation of pollutants or destruction of bacteria [24,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Compared with BiOBr [18], AgBr [45] has a narrower band gap and higher visible-light absorption. Moreover, the two materials have matching energy band structures, according to the data reported in the literature [18,44], and which can effectively separate photogenerated electrons and holes to achieve enhanced photoactivity

AgBr nanoparticles decorated BiPO4 microrod: a novel p–n heterojunction with enhanced photocatalytic activities

“…Also, as reported in Table 1, the specific surface area (SBET) of AgBr/BiPO4 heterojunction slightly increased with the increasing of the content of AgBr. [47][48][49][50] According to equation (), the band gap energy (Eg) of the resulting samples can be estimated by a plot of (αhν) 2 versus the photon energy (hν).…”

Improved photocatalytic Bi2WO6/BiOCl heterojunctions: One-step synthesis via an ionic-liquid assisted ultrasonic method and first-principles calculations

“…Semiconductor photocatalyst has been widely used for environmental pollutants removal and solar energy conversion [1][2][3]. Recently, Bi2WO6 has attracted extensive attention due to its narrow band gap (the band gap is 2.8eV) and photocatalytic activity under visible light [4][5][6].…”

Facile Green Synthesis of BiOBr Nanostructures with Superior Visible-Light-Driven Photocatalytic Activity

“…The optical absorption region of semiconductors can be evaluated by the energy of band gap (E g ) and analyzed by the following equation: αhυ = A(hυ − E g ) n/2 where E g , υ, α, and A are the band gap energy, frequency of light, absorption coefficient, and a constant, respectively, for direct transition ( n = 1) and for indirect transition ( n = 4). The n value was 4 for BiOBr [ 54 ]. The Tauc plots of BiOBr-C and BiOBr-G are shown in Figure 5 b.…”