Radiation-induced synthesis of α-Al₂O₃ supported nickel clusters: Characterization and catalytic properties

详细信息	查看全文 | 推荐本文 |

• 作者：N. Keghouche ; S. Chettibi ; F. Latrè ; che ; M.M. Bettahar ; J. Belloni and J.L. Marignier
• 关键词：Ni ; α ; -Al₂O₃ ; Radiolysis ; Catalyst ; Steam reforming ; H₂ chemisorption
• 刊名：Radiation Physics and Chemistry
• 出版年：2005
• 期刊代码：68_0969806x
• 类别：ph
• 出版时间：2005
• 卷：74
• 期：3-4
• 页码：185-200
• 文件大小：457 K

摘要

A series of Ni aggregates supported on me="mml13">method=retrieve&_udi=B6TVT-4GFCPR0-1&_mathId=mml13&_user=10&_cdi=5543&_rdoc=11&_handle=V-WA-A-W-WU-MsSAYWW-UUA-U-AABZBZZZUZ-AABBEVDVUZ-CAYDCWBZD-WU-U&_acct=C000050221&_version=1&_userid=10&md5=82c4764c0923eb2cdb2d799b26efb70b" title="Click to view the MathML source">α-Al₂O₃ at different nickel contents are prepared by ionic exchange of Ni²⁺ followed by γ-irradiation under inert atmosphere. Characterization techniques are used at each step to select the elaboration conditions optimized for their use as catalysts. X-ray diffraction demonstrates the presence, after the Ni²⁺ adsorption step, of the phases (NiO)₂(Al₂O₃)₉ and (NiO)(Al₂O₃)₁₆ that are favourable to further performances of the catalyst. After radiolysis, the phases of the oxide NiO and the metal Ni are observed. The relative amount of the Ni metal phase increases with the initial Ni²⁺ content. The nickel clusters (prepared from the complex [Ni(NH₃)₆]²⁺), imaged by Scanning Electron Microscope (SEM)/EDS, are highly dispersed. The H₂ adsorption and thermodesorption study by chemisorption and H₂-TPD indicates that the sites of the catalyst are occupied by hydrogen generated during irradiation. After H₂ treatment at 350 °C, it shows high hydrogen adsorption/desorption capacity. When tested in the steam-reforming methane reaction (CH₄+H₂O→CO+3H₂), the radiolytic Ni/me="mml14">method=retrieve&_udi=B6TVT-4GFCPR0-1&_mathId=mml14&_user=10&_cdi=5543&_rdoc=11&_handle=V-WA-A-W-WU-MsSAYWW-UUA-U-AABZBZZZUZ-AABBEVDVUZ-CAYDCWBZD-WU-U&_acct=C000050221&_version=1&_userid=10&md5=6228c3632ba991053e6fff008daf0f53" title="Click to view the MathML source">α-Al₂O₃ samples exhibit quite promising catalytic properties, namely a high activity and a remarkably high selectivity in CO even at moderate temperature (80%at 550 °C with a conversion of 60%).