title: Metastable β-Bi2O3 Nanoparticles with Potential for Photocatalytic Water Purification Using Visible Light Irradiation.
abstract: Photocatalytic studies under visible light irradiation using nanosized β-Bi2O3 are reported. β-Bi2O3 nanoparticles are prepared starting from the well-defined bismuth oxido cluster [Bi38O45(OMc)24(DMSO)9]⋅2 DMSO⋅7 H2O (OMc=O2CC3H5) using a straightforward hydrolysis and annealing protocol. Powder X-ray diffraction studies, transmission electron microscopy, diffuse reflectance UV/Vis spectroscopy and nitrogen adsorption measurements (using the Brunauer-Emmett-Teller (BET) theory) are used for the characterization of the as-prepared β-Bi2O3. By time-dependent annealing, the crystallite size can be controlled between (17±2) nm and (45±5) nm with BET surface areas of 7 to 29 m(2) g(-1). The indirect band gap of the as-prepared β-Bi2O3 amounts to (2.15±0.05) eV. The decomposition rates for rhodamine B (RhB) solutions are in the range of 2.46×10(-5) to 4.01×10(-4) s(-1) and depend on the crystallite size, amount of catalyst and concentration of RhB. Photocorrosion experiments have shown the formation of Bi2O2CO3 after several catalytic cycles. However, the catalyst can be recycled to phase-pure β-Bi2O3 nanoparticles by annealing for one hour under argon atmosphere at 380 °C. Furthermore, the photocatalytic activity of as-prepared β-Bi2O3 nanoparticles for the decomposition of phenol, 4-chlorophenol, 2,4-dichlorphenol, 4-nitrophenol, triclosan and ethinyl estradiol is demonstrated.
authors.affiliation: Fakultät für Naturwissenschaften, Institut für Chemie, Professur Koordinationschemie, Technische Universität Chemnitz, Straße der Nationen 62 09111 Chemnitz (Germany) E-mail: michael.mehring@chemie.tu-chemnitz.de.
authors.forename: Maik
authors.initials: M
authors.lastname: Schlesinger
authors.affiliation: Fakultät für Naturwissenschaften, Institut für Chemie, Professur Koordinationschemie, Technische Universität Chemnitz, Straße der Nationen 62 09111 Chemnitz (Germany) E-mail: michael.mehring@chemie.tu-chemnitz.de.
authors.forename: Marcus
authors.initials: M
authors.lastname: Weber
authors.affiliation: Fakultät für Naturwissenschaften, Institut für Physik, Professur Analytik an Festkörperoberflächen, Technische Universität Chemnitz, Reichenhainer Straße 70 09126 Chemnitz (Germany).
authors.forename: Steffen
authors.initials: S
authors.lastname: Schulze
authors.affiliation: Fakultät für Naturwissenschaften, Institut für Physik, Professur Analytik an Festkörperoberflächen, Technische Universität Chemnitz, Reichenhainer Straße 70 09126 Chemnitz (Germany).
authors.forename: Michael
authors.initials: M
authors.lastname: Hietschold
authors.affiliation: Fakultät für Naturwissenschaften, Institut für Chemie, Professur Koordinationschemie, Technische Universität Chemnitz, Straße der Nationen 62 09111 Chemnitz (Germany) E-mail: michael.mehring@chemie.tu-chemnitz.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Mehring
keywords: bismuth oxide nanoparticles; bismuth oxido clusters; organic pollutants; photocatalysis; visible light irradiation