Effect of ZrO2 promoter on structure and catalytic activity of the Ni/SiO2 catalyst for CO methanation in hydrogen-rich gases
Effect of ZrO2 promoter on structure and catalytic activity of the Ni/SiO2 catalyst for CO methanation in hydrogen-rich gases
复制标题
ZrO2助剂对Ni/SiO2富氢气体CO甲烷化催化剂结构及催化活性的影响
DOI：
10.1016/j.cattod.2010.07.016
复制
发表时间：
2010-12-22
期刊：
影响因子：
5.3
通讯作者：
Zhao, Yongxiang
中科院分区：
文献类型：
--
作者：
Wang, Yongzhao;Wu, Ruifang;Zhao, Yongxiang
采用初湿浸渍法制备了未改性的（Ni/SiO（2））和含ZrO（2）改性的（Ni/ZrO（2）-SiO（2））SiO2气凝胶负载Ni基催化剂。研究了它们在富氢气体中CO甲烷化反应中的催化活性用连续流动微反应器研究了CO。结果表明，Ni/ZrO（2）-SiO（2）催化剂具有较高的催化活性，在240 ℃时CO可完全转化为CH（4）。然而，在相同的反应条件下，在Ni/SiO（2）催化剂上，直到温度升高到320 ℃，CO才能完全转化。通过FT-IR、XRD、TEM、NH（3）-TPD、H（2）-TPR和H（2）-TPD等手段对ZrO 2-SiO2载体进行了表征，结果表明，Si-O-Zr键的形成使ZrO 2-SiO2载体的酸强度和酸量增加。酸性的变化导致NiO物种与ZrO（2）-SiO（2）载体之间的相互作用增强，从而提高了NiO物种的分散度和还原度。因此，Ni/ZrO（2）-SiO（2）催化剂具有较小的Ni晶粒尺寸、较高的Ni分散度、较多的活性Ni物种和较强的H（2）吸附能力，这可能是其具有较高CO甲烷化活性的原因。(C)2010 Elsevier B. V.保留所有权利。
Ni-based catalysts supported on SiO(2) aerogel that is unpromoted (Ni/SiO(2)) or promoted (Ni/ZrO(2)-SiO(2)) with ZrO(2) are prepared by the incipient-wetness impregnation method. Their catalytic activities for CO methanation in hydrogen-rich gases with 1 vol.% CO are studied with a continuous flowing microreactor. It is found that the Ni/ZrO(2)-SiO(2) catalyst shows higher catalytic activity, over which CO can be completely converted into CH(4) at 240 degrees C. However, CO cannot be completely converted until the temperature was raised to 320 degrees C over the Ni/SiO(2) catalyst under the same reaction conditions. Characterizations using FT-IR, XRD, TEM, NH(3)-TPD, H(2)-TPR and H(2)-TPD suggest that the formation of Si-O-Zr bond results in stronger acid strength and larger amounts of acid of the ZrO(2)-SiO(2) support. The changes of acidity lead to the increase of the interaction between NiO species and the ZrO(2)-SiO(2) support and then enhance the dispersion degree and the reduction degree of NiO species. Thus, the Ni/ZrO(2)-SiO(2) catalyst possesses smaller Ni crystallite size, higher Ni dispersion, more active Ni species and stronger adsorption ability for H(2), which may contribute to its higher catalytic activity for CO methanation. (C) 2010 Elsevier B.V. All rights reserved.