bismuth-oxybromide and methyl-orange

Photocatalysis is extensively investigated as a green, efficient and promising technique for environmental remediation. In this study, a series of template free In-doped BiOBr

Topics: Azo Compounds; Bismuth; Catalysis; Coloring Agents; Environmental Pollutants; Environmental Restoration and Remediation; Indium; Iodine Compounds; Light; Methylene Blue; Nanostructures; Photolysis; Rhodamines; Surface Properties; Temperature

In recent years, considerable effort has been devoted to finding novel enzyme mimetics with improved catalytic activities. However, the insightful understanding of such catalytic process is still elusive. In this paper, we report for the first time a typical photoactive layer-structured BiOBr as a novel biomimetic catalyst possessing highly efficient intrinsic peroxidase-like activity. Moreover, we have experimentally achieved high dark peroxidase-like catalytic activity in BiOBr microspheres and provided some new insights into the light-enhanced peroxidase-like catalytic property. On the basis of a typical color reaction derived from catalytic oxidation of peroxidase substrates over BiOBr microspheres with H2O2, the simple and sensitive colorimetric assays for detection of H2O2, glucose and ascorbic acid were successfully established. More interestingly, the BiOBr microspheres showed strong ability towards activation of H2O2, displaying excellent dark catalytic activity for the degradation of organic dye. It is therefore believed that our findings in this study could open up the possibility of utilizing BiOBr as enzymatic mimics in biotechnology and environmental remediation.

Topics: Ascorbic Acid; Azo Compounds; Biocompatible Materials; Biosensing Techniques; Bismuth; Catalysis; Colorimetry; Coloring Agents; Glucose; Hydrogen Peroxide; Kinetics; Light; Microspheres; Oxidation-Reduction; Peroxidase; Water Pollutants, Chemical

Two kinds of BiOBr nanosheets-assembled microspheres were successfully prepared via a facile, rapid and reliable microwave-assisted solvothermal route, employing Bi(NO(3))(3)·5H(2)O and cetyltrimethylammonium bromide (CTAB) as starting reagents in the absence or presence of oleic acid. The phase and morphology of the products were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Experiments indicated that the formation of these building blocks of microspheres could be ascribed to the self-assembly of nanoparticles according to mesocrystal growth mode. Interestingly, both samples exhibited not only strong adsorption abilities, but also excellent photocatalytic activities for methyl orange (MO), rhodamine B (RhB) and phenol. The resulting BiOBr hierarchical microspheres are very promising adsorbents and photocatalysts for the treatment of organic pollutants.

Topics: Adsorption; Azo Compounds; Bismuth; Catalysis; Cetrimonium; Cetrimonium Compounds; Microspheres; Microwaves; Nanostructures; Nanotechnology; Phenols; Photochemical Processes; Rhodamines

Visible-light-induced photocatalyst BiOBr has been synthesized by a hydrothermal method, in which cetyltrimethylammonium bromide (CTAB) acted not only as the template but also the Br source. A possible formation mechanism of BiOBr lamellar structure with the assistance of CTAB under hydrothermal condition was proposed. The photocatalytic activities were evaluated by the degradation of methyl orange (MO) at pH 4.5 under visible-light irradiation (lambda>420 nm). The lamellar BiOBr prepared in 100mL CTAB solution with the molar ratio of CTAB/Bi(NO(3))(3) (R)=2:1 at the hydrothermal temperature of 160 degrees C for 24h exhibited excellent visible-light-driven photocatalytic efficiency, which was up to 96% within 120 min. This was about four times higher than that of the BiOBr synthesized by KBr. After five recycles, the catalyst did not exhibit any significant loss of photocatalytic activity, confirming the photocatalyst is essentially stable. Close investigation revealed that the size, the band gap, and the structure of as-prepared BiOBr affected the photocatalytic activities.

Topics: Azo Compounds; Bismuth; Catalysis; Cetrimonium; Cetrimonium Compounds; Environmental Restoration and Remediation; Light; Molecular Structure; Photochemical Processes