One‐Pot Miniemulsion‐Mediated Route to BiOBr Hollow Microspheres with Highly Efficient Photocatalytic Activity

Abstract

Due to the shape-dependent physical/chemical properties of inorganic materials, methodological syntheses of their ordered architectures have always been the hotspots in materials chemistry. In particular, attention has been paid to the self-assembly of the hierarchical macro-, meso-, or microstructures with hollow voids, which possess the combined features of nanosized building blocks and the organized architectures, in virtue of their potential applications in drug delivery, lithium-ion batteries, and catalysis.[1] Numerous synthetic methods have been exploited to accelerate the realization of special microstructures. For example, the conventional template-directed synthesis turns out to be a universal and effective approach, in which hard or soft templates, such as polymer supports, [2] carbon spheres, [3] and organic surfactants [4] are employed to tailor the growth process. Nevertheless, the template-directed routes usually subject to the tedious procedures and possible impurities introduced. Ideally, people would prefer template-free routes to the inorganic materials with hollow interiors. As an alternative route to templates, emulsion and miniemulsion systems, which are thermodynamically instable, have been employed to produce hollow structures. [5][6][7][8] Derived from the limited miscibility of the mixed solvents, microsized to even larger emulsions, which can perform as the microreactors, are produced by the micro-heterogeneities by means of sonicating or stirring. [9,10] However, most of the syntheses require large quantities of surfactants to generate micelles, thereby increasing the complexity, and one-pot rational control of the hollow architectures still remains a challenge.Recently, semiconductor photocatalysis has been regarded as an effective resolution to the hydrogen production and organic pollutants removal. [11][12][13][14][15][16][17] The conventional semiconductors, TiO 2 and WO 3 , however, are restricted by their deficient visible-light absorption or high recombination rate of the photogenerated carriers. [11,14] In search of highly visiblelight-active photocatalysts, great efforts have been dedicated to the bandgap regulation and quantum efficiency improvement. As a ternary semiconductor, BiOBr crystallizes in a layered structure composed of [Bi 2 O 2 ] 2 + layers interleaved with double Br layers. Previously, BiOBr has exhibited considerable visible-light photocatalytic performance in the degradation of organic contaminants.[18] So far, a variety of BiOBr nano/micro-structures, including nanoplates, nanobelts, and microspheres, have been fabricated by numerous methods. [18,19] However, controlling the self-assembly of the BiOBr building units, such as nanosheets, into their hollow architectures is still a bottleneck. Moreover, the photocatalytic activity of BiOBr is far from efficient for practical applications and it is indispensable to boost the photocatalytic efficiency by microstructure modulations.Herein, we report a facile one-pot approach to the uniform BiOBr hollow microspher...

Metastableh-MoO3and stableα-MoO3microstructures: controllable synthesis, growth mechanism and their enhanced photocatalytic activity

“…It is reported that the photocatalytic performance of catalysts is largely morphology dependent, which is determined by the recombination rate of the photogenerated electrons and holes. [24] Rough surface and pores would enable catalyst that has higher adsorption capacity and provide more accessible active sites for photocatalytic reaction. In addition, smaller scale of nanoplates would also reduce the recombination opportunities of the photogenerated electronÀhole pairs, and the photogenerated carriers could effectively move to the surface of catalyst to degrade the adsorbed organic dye molecules.…”

Preparation and first-principles study for electronic structures of BiOI/BiOCl composites with highly improved photocatalytic and adsorption performances

“…The bismuth oxyhalides (BiOX, X = Cl, Br, I), a sequences of ternary semiconductors, have been found as promising materials for organic matter degradations due to their unique and excellent electrical, magnetic, optical, luminescent and catalytic properties [1][2][3][4][5][6][7][8]. Recently, considerable attentions have been paid to prepare BiOX with variety of morphologies and structures [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Effect of solvents on morphology and photocatalytic activity of BiOBr synthesized by solvothermal method

“…For example, Feng et al synthesized mesoporous BiOBr 3-D microspheres with highly efficient photocatalytic activity in ethanol-mediated condition [7], while Chen et al demonstrated synthesis of BiOBr nanoplateassembled microflowers in EG-mediated condition [8]. Very recently, using 2-methoxyethanol as reaction media, BiOBr hollow microspheres with higher efficient photocatalytic activity were obtained [9]. Based on these studies, it is found that the different solvents often lead to the different morphologies.…”