Interfacial activation of catalytically inert Au (6.7 nm)-Fe3O4 dumbbell nanoparticles for CO oxidation

AbstractAu nanoparticles epitaxially grown on Fe3O4 in Au (6.7 nm)-Fe3O4 dumbbell nanoparticles exhibit excellent stability against sintering, but display negligible catalytic activity in CO oxidation. Starting from various supported Au (6.7 nm)-Fe3O4 catalysts prepared by the colloidal deposition method, we have unambiguously identified the significance of the Au-TiO2 interface in CO oxidation, without any possible size effect of Au. In situ thermal decomposition of TiO2 precursors on Au-Fe3O4 was found to be an effective way to increase the Au-TiO2 interface and thereby optimize the catalytic performance of TiO2-supported Au-Fe3O4 dumbbell nanoparticles. By reducing the size of Fe3O4 from 15.2 to 4.9 nm, the Au-TiO2 contact was further increased so that the resulting TiO2-supported Au (6.7 nm)-Fe3O4 (4.9 nm) dumbbell particles become highly efficient catalysts for CO oxidation at room temperature.

[1]  N. Zheng,et al.  One-step one-phase synthesis of monodisperse noble-metallic nanoparticles and their colloidal crystals. , 2006, Journal of the American Chemical Society.

[2]  Shouheng Sun,et al.  Dumbbell-like bifunctional Au-Fe3O4 nanoparticles. , 2005, Nano letters.

[3]  Masatake Haruta,et al.  Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide , 1989 .

[4]  David Thompson,et al.  Catalysis By Gold , 1999 .

[5]  M. Haruta Gold as a novel catalyst in the 21st century: Preparation, working mechanism and applications , 2004 .

[6]  Shouheng Sun,et al.  Colloidal deposition synthesis of supported gold nanocatalysts based on Au-Fe3O4 dumbbell nanoparticles. , 2008, Chemical communications.

[7]  M. Haruta,et al.  A Kinetic and Adsorption Study of CO Oxidation over Unsupported Fine Gold Powder and over Gold Supported on Titanium Dioxide , 1999 .

[8]  Tymish Y. Ohulchanskyy,et al.  A general approach to binary and ternary hybrid nanocrystals. , 2006, Nano letters.

[9]  G. Hutchings,et al.  Tunable gold catalysts for selective hydrocarbon oxidation under mild conditions , 2005, Nature.

[10]  Masatake Haruta,et al.  Size- and support-dependency in the catalysis of gold , 1997 .

[11]  Nanfeng Zheng,et al.  A general synthetic strategy for oxide-supported metal nanoparticle catalysts. , 2006, Journal of the American Chemical Society.

[12]  L. Guczi,et al.  Role of Preparation Techniques in the Activity of Au/TiO2 Nanostructures Stabilised on SiO2: CO and Preferential CO Oxidation , 2009 .

[13]  Zhen Ma,et al.  Au/MxOy/TiO2 catalysts for CO oxidation: Promotional effect of main-group, transition, and rare-earth metal oxide additives , 2007 .

[14]  A. Corma,et al.  Chemoselective Hydrogenation of Nitro Compounds with Supported Gold Catalysts , 2006, Science.

[15]  S. Overbury,et al.  XAS Study of Au Supported on TiO2: Influence of Oxidation State and Particle Size on Catalytic Activity , 2004 .

[16]  A. Corma,et al.  Gold-Catalyzed Synthesis of Aromatic Azo Compounds from Anilines and Nitroaromatics , 2008, Science.

[17]  Masatake Haruta,et al.  Catalysis of Gold Nanoparticles Deposited on Metal Oxides , 2002 .

[18]  J. Grunwaldt,et al.  Preparation of Supported Gold Catalysts for Low-Temperature CO Oxidation via “Size-Controlled” Gold Colloids , 1999 .

[19]  M. S. Chen,et al.  The Structure of Catalytically Active Gold on Titania , 2004, Science.

[20]  Masatake Haruta,et al.  When gold is not noble: catalysis by nanoparticles. , 2003, Chemical record.

[21]  M. Bowker,et al.  Low temperature CO oxidation on supported and unsupported gold compounds , 2005 .

[22]  Ferdi Schüth,et al.  Support effect in high activity gold catalysts for CO oxidation. , 2006, Journal of the American Chemical Society.

[23]  Shouheng Sun,et al.  A facile synthesis of monodisperse Au nanoparticles and their catalysis of CO oxidation , 2008 .

[24]  Brian F. G. Johnson,et al.  Selective oxidation with dioxygen by gold nanoparticle catalysts derived from 55-atom clusters , 2008, Nature.

[25]  Hiroshi Sano,et al.  Novel Gold Catalysts for the Oxidation of Carbon Monoxide at a Temperature far Below 0 °C , 1987 .

[26]  D. Goodman,et al.  Catalytically active gold: from nanoparticles to ultrathin films. , 2006, Accounts of chemical research.

[27]  Avelino Corma,et al.  Supported gold nanoparticles as catalysts for organic reactions. , 2008, Chemical Society reviews.

[28]  E. McFarland,et al.  Direct propylene epoxidation on chemically reduced Au nanoparticles supported on titania. , 2004, Chemical communications.