Block copolymer-templated BiFeO3 nanoarchitectures composed of phase-pure crystallites intermingled with a continuous mesoporosity: Effective visible-light photocatalysts?
Autor: | Christian Suchomski, Torsten Brezesinski, Christian Reitz, Christoph Weidmann |
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Rok vydání: | 2011 |
Předmět: |
Materials science
Nanotechnology Condensed Matter Physics Atomic and Molecular Physics and Optics Nanocrystalline material Amorphous solid law.invention Secondary ion mass spectrometry symbols.namesake chemistry.chemical_compound X-ray photoelectron spectroscopy chemistry Chemical engineering law symbols General Materials Science Crystallite Electrical and Electronic Engineering Crystallization Raman spectroscopy Bismuth ferrite |
Zdroj: | Nano Research. 4:414-424 |
ISSN: | 1998-0000 1998-0124 |
Popis: | Herein is reported the soft-templating synthesis of visible-light photoactive bismuth ferrite (BiFeO3) nanoarchitectures in the form of thin films using a poly(ethylene-co-butylene)-block-poly(ethylene oxide) diblock copolymer as the structure-directing agent. We establish that (1) the self-assembled materials employed in this work are highly crystalline after annealing at 550 °C in air and that (2) neither the bismuth-poor Bi2Fe4O9 phase nor other impurity phases are formed. We further show that there is a distinct restructuring of the high quality cubic pore network of amorphous BiFeO3 during crystallization. This restructuring leads to films with a unique architecture that is composed of anisotropic crystallites intermingled with a continuous mesoporosity. While this article focuses on the characterization of these novel materials by electron microscopy, krypton physisorption, grazing incidence small-angle X-ray scattering, time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy, UV-vis and Raman spectroscopy, we also examine the photocatalytic properties and show the benefits of the combination of mesoporosity and nanocrystallinity. Templated BiFeO3 thin films (25% porosity) with a direct optical band gap at 2.9 eV exhibit a catalytic activity for the degradation of rhodamine B much better than that of nontemplated samples. We attribute this improvement to the nanoscale porosity, which provides for more available active sites on the photocatalyst. |
Databáze: | OpenAIRE |
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