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In situ synthesis of TiO2-functionalized metal nanoparticles / David M. King in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 352-360 Titre : In situ synthesis of TiO2-functionalized metal nanoparticles Type de document : texte imprimé Auteurs : David M. King, Editeur scientifique ; Yun Zhou, Editeur scientifique ; Louis F. Hakim, Editeur scientifique Année de publication : 2009 Article en page(s) : P. 352-360 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal  nanoparticles  Atomic  layer  deposition  (ALD)  Gas-phase  TiO2  ALD Résumé : The ability to prepare and functionalize passivated nanosized metal powders was demonstrated using TiO2 films that were deposited via atomic layer deposition (ALD). Metal nanopowders were synthesized from the dehydration and subsequent decomposition of bulk quantities of metal oxalates in a fluidized-bed reactor. The gas-phase TiO2 ALD coating process was used to passivate these particles in situ, which alleviated the need to expose the oxygen-sensitive materials to air. Metal oxalate size reduction was achieved using a cryogenic milling process that reduced the micrometer-sized oxalate feed powder and yielded metal nanopowders with an average primary diameter of ∼50 nm. The metal oxalates that have received the most attention are those of iron, nickel, cobalt, and copper. Al2O3-based ALD films have been deposited on each of these metals, whereas TiO2:metal nanocomposite powder research has been performed here and is the basis for this work. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800196h [article] In situ synthesis of TiO2-functionalized metal nanoparticles [texte imprimé] / David M. King, Editeur scientifique ; Yun Zhou, Editeur scientifique ; Louis F. Hakim, Editeur scientifique . - 2009 . - P. 352-360. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 352-360 Mots-clés : Metal  nanoparticles  Atomic  layer  deposition  (ALD)  Gas-phase  TiO2  ALD Résumé : The ability to prepare and functionalize passivated nanosized metal powders was demonstrated using TiO2 films that were deposited via atomic layer deposition (ALD). Metal nanopowders were synthesized from the dehydration and subsequent decomposition of bulk quantities of metal oxalates in a fluidized-bed reactor. The gas-phase TiO2 ALD coating process was used to passivate these particles in situ, which alleviated the need to expose the oxygen-sensitive materials to air. Metal oxalate size reduction was achieved using a cryogenic milling process that reduced the micrometer-sized oxalate feed powder and yielded metal nanopowders with an average primary diameter of ∼50 nm. The metal oxalates that have received the most attention are those of iron, nickel, cobalt, and copper. Al2O3-based ALD films have been deposited on each of these metals, whereas TiO2:metal nanocomposite powder research has been performed here and is the basis for this work. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800196h

Synthesis of photoactive magnetic nanoparticles with atomic layer deposition / Yun Zhou in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6964–6971 Titre : Synthesis of photoactive magnetic nanoparticles with atomic layer deposition Type de document : texte imprimé Auteurs : Yun Zhou, Auteur ; David M. King, Auteur ; Jianhua Li, Auteur Année de publication : 2010 Article en page(s) : pp 6964–6971 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Photoactive  Magnetic  Nanoparticles. Résumé : Iron-based magnetic nanoparticles have been produced by decomposition of iron oxalate powder. The micrometer-size iron oxalate powder was first ground by use of a cryogenic milling process. A titanium dioxide (TiO2) thin film was then deposited on the synthesized iron nanoparticles with an in situ atomic layer deposition (ALD) process at 100 °C with TiCl4 and H2O2 as precursors. However, because of the high surface area, the iron nanoparticles were unstable and spontaneously oxidized when exposed to H2O2 during the TiO2 ALD process, thus reducing the magnetic moment of the core particles. As an improvement in the process, prior to the TiO2 deposition, an aluminum nitride (AlN) film was deposited in situ to coat and passivate the iron core particles. The AlN ALD was performed at 250 °C with trimethylaluminium (TMA) and ammonia (NH3) as precursors. This passivation provided a significant decrease in the iron oxidation as determined by X-ray diffraction and magnetization measurements. Photoactivity of the TiO2 film was demonstrated by decomposition of methylene blue solution under ultraviolet irradiation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901712q [article] Synthesis of photoactive magnetic nanoparticles with atomic layer deposition [texte imprimé] / Yun Zhou, Auteur ; David M. King, Auteur ; Jianhua Li, Auteur . - 2010 . - pp 6964–6971. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6964–6971 Mots-clés : Photoactive  Magnetic  Nanoparticles. Résumé : Iron-based magnetic nanoparticles have been produced by decomposition of iron oxalate powder. The micrometer-size iron oxalate powder was first ground by use of a cryogenic milling process. A titanium dioxide (TiO2) thin film was then deposited on the synthesized iron nanoparticles with an in situ atomic layer deposition (ALD) process at 100 °C with TiCl4 and H2O2 as precursors. However, because of the high surface area, the iron nanoparticles were unstable and spontaneously oxidized when exposed to H2O2 during the TiO2 ALD process, thus reducing the magnetic moment of the core particles. As an improvement in the process, prior to the TiO2 deposition, an aluminum nitride (AlN) film was deposited in situ to coat and passivate the iron core particles. The AlN ALD was performed at 250 °C with trimethylaluminium (TMA) and ammonia (NH3) as precursors. This passivation provided a significant decrease in the iron oxidation as determined by X-ray diffraction and magnetization measurements. Photoactivity of the TiO2 film was demonstrated by decomposition of methylene blue solution under ultraviolet irradiation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901712q