Simple Solvothermal Routes to Synthesize 3D BiOBr_xI_1-x Microspheres and Their Visible-Light-Induced Photocatalytic Properties

Abstract

The band structure-controlled solid solution of BiOBr x I 1-x was successfully synthesized by a simple solvothermal route. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, UVÀvis diffuse reflectance spectroscopy, and nitrogen sorption/desorption. The resulting BiOBr x I 1-x samples were phase-pure and of three-dimensional (3D) microspheres composed of nanoplates. The samples with different x values exhibited composition-dependent absorption properties in the visible light region and the bandgaps were estimated to be between 1.89 and 2.53 eV. Rhodamine B (RhB) photocatalytic degradation experiments showed that these samples possessed excellent and composition-dependent performance. The highest catalytic performance of the 3D BiOBr 0.2 I 0.8 microspheres may derive from a synergetic effect, including higher surface area, porous structure, and enhancement of light absorbance. Moreover, on the basis of the analysis of the valence band and conduction band, a possible mechanism of photocatalytic activity of BiOBr x I 1-x samples was also proposed.

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

“…These regular changes in XRD peaks and cell parameters as a function of I content strongly declare that the obtained BiOBr x I 1−x products belong to a group of solid solutions [27]. In addition, there are no other diffraction peaks of impurity, which implies that all the atoms entered into the crystal lattice and the stoichiometric value x in BiOBr x I 1−x was accurately determined by the initial proportion of Br and I sources in the preparation procedure [36,39]. The relative intensities of (001), (002), and (004) peaks gradually become stronger with increasing I content; on the contrary, that of (101) peak gradually weakens.…”

One-pot synthesis of novel flower-like BiOBr0.9I0.1/BiOI heterojunction with largely enhanced electron-hole separation efficiency and photocatalytic performances

“…For example, I -ion doped BiOBr had little E g values (1.93 eV) through raising the VB level. However, the recombination rate of photocarriers could also be strengthened with the decreasing of band gap energy [20][21][22].…”

Controlled hydrothermal synthesis of BiOxCly/BiOmIn composites exhibiting visible-light photocatalytic degradation of crystal violet

“…However, the characteristic emission peak at approximately 2.01 eV nearly disappeared for BiO x Cl y /BiO m I n , indicating that the recombination of photogenerated charge carriers was greatly inhibited. The efficient separation of charge might increase the lifetime of charge carriers and enhance the efficiency of interfacial charge transfer to the adsorbed substrates, thus improving the photocatalytic activity [12,31,32]. The low relative CL intensities of BC1I2-7-110-12 and BC2I1-110-4-12 composites, as shown in Fig.…”