Characterization of aerogel Ni/Al2O3 catalysts and investigation on their stability for CH4-CO2 reforming in a fluidized bed
Characterization of aerogel Ni/Al2O3 catalysts and investigation on their stability for CH4-CO2 reforming in a fluidized bed
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DOI：
10.1016/j.fuproc.2008.08.004
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发表时间：
2009-01-01
影响因子：
7.5
通讯作者：
Li, Hongzhong
中科院分区：
文献类型：
--
作者：
Hao, Zhigang;Zhu, Qingshan;Li, Hongzhong
采用溶胶-凝胶法结合超临界干燥工艺制备纳米气凝胶Ni/Al2O3催化剂，在流化床反应器中对CH4-CO2的重整进行了研究。采用BET、XRD、H-2-TPR和H-2-TPD技术对催化剂进行了表征。与浸渍催化剂相比，气凝胶催化剂具有更高的比表面积、更低的堆积密度、更小的Ni粒径、更强的金属-载体相互作用和更高的Ni分散度。所有气凝胶催化剂均表现出比浸渍催化剂更好的催化活性和稳定性。在48 h重整过程中测试的催化稳定性取决于它们的Ni负载。对废催化剂的表征表明，气凝胶催化剂上只形成了有限的石墨碳，而浸渍催化剂上则形成了大量丝状石墨碳，导致催化活性明显下降。镍含量为10%的气凝胶催化剂具有较小的镍颗粒尺寸和较强的金属-载体相互作用，具有较好的催化稳定性和最低的碳沉积率。(C) 2008 Elsevier B.V.版权所有
The CH4-CO2 reforming was investigated in a fluidized bed reactor using nano-sized aerogel Ni/Al2O3 catalysts, which were prepared via a sol-gel method combined with a supercritical drying process. The catalysts were characterized with BET, XRD, H-2-TPR and H-2-TPD techniques. Compared with the impregnation catalyst, aerogel catalysts exhibited higher specific surface areas, lower bulk density, smaller Ni particle sizes, stronger metal-support interaction and higher Ni dispersion degrees. All tested aerogel catalysts showed better catalytic activities and stability than the impregnation catalyst. Their catalytic stability tested during 48 h reforming was dependent on their Ni loadings. Characterizations of spent catalysts indicated that only limited graphitic carbon formed on the aerogel catalyst, while massive graphitic carbon with filamentous morphology was observed for the impregnation catalyst, leading to significant catalytic activity degradation. An aerogel catalyst containing 10% Ni showed the best catalytic stability and the lowest rate of carbon deposition among the aerogel catalysts due to its small Ni particle size and strong metal-support interaction. (C) 2008 Elsevier B.V. All rights reserved.