物理化学学报 >> 2016, Vol. 32 >> Issue (11): 2803-2810.doi: 10.3866/PKU.WHXB201607291

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介孔γ-Al2O3负载的高分散Ni-Ce-Zr氧化物的制备及其二氧化碳甲烷化研究

聂望欣,邹秀晶*(),汪学广*(),丁伟中,鲁雄刚   

  • 收稿日期:2016-06-02 发布日期:2016-11-08
  • 通讯作者: 邹秀晶,汪学广 E-mail:xjzou@shu.edu.cn;wxg228@shu.edu.cn
  • 基金资助:
    上海市教育委员会科研项目;国家重点基础研究发展规划项目（973）(2014CB643403);国家杰出青年科学基金(51225401);上海市科委基础重点项目(14JC1491400);the Innovation Program of Shanghai Municipal Education Commission;National Key Basic Research Program of China (973)(2014CB643403);National Science Fund for Distinguished Young Scholars, China(51225401);Basic Major Research Program of Science and Technology Commission Foundation of Shanghai, China(14JC1491400)

Preparation of Highly Dispersed Ni-Ce-Zr Oxides over Mesoporous γ-Alumina and Their Catalytic Properties for CO2 Methanation

Wang-Xin NIE,Xiu-Jing ZOU*(),Xue-Guang WANG*(),Wei-Zhong DING,Xiong-Gang LU   

  • Received:2016-06-02 Published:2016-11-08
  • Contact: Xiu-Jing ZOU,Xue-Guang WANG E-mail:xjzou@shu.edu.cn;wxg228@shu.edu.cn
  • Supported by:
    上海市教育委员会科研项目;国家重点基础研究发展规划项目（973）(2014CB643403);国家杰出青年科学基金(51225401);上海市科委基础重点项目(14JC1491400);the Innovation Program of Shanghai Municipal Education Commission;National Key Basic Research Program of China (973)(2014CB643403);National Science Fund for Distinguished Young Scholars, China(51225401);Basic Major Research Program of Science and Technology Commission Foundation of Shanghai, China(14JC1491400)

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摘要：

采用柠檬酸（CA）-浸渍法制备了介孔γ-Al2O3（γ-MA）负载的高分散Ni-Ce-Zr氧化物，并将其用于二氧化碳甲烷化反应。研究了柠檬酸加入量对催化剂物理化学性质及催化性能的影响。结果表明，柠檬酸的加入可明显提高Ni-Ce-Zr氧化物在γ-Al2O3表面的分散性，同时可以增加镍氧化物与载体间的相互作用。制备材料经氢气还原后得到Ni-Ce-Zr/γ-MA催化剂，镍纳米颗粒均匀分散于γ-Al2O3表面。Ni-Ce-Zr/γ-MA催化剂在二氧化碳甲烷化反应中表现出了较高的反应活性和几乎100%的甲烷选择性。反应活性随CA/（Ni+Ce+Zr）摩尔比的增加而增加，主要是由于镍颗粒尺寸的减小和Ni-Ce-ZrOx物种电子和结构性质的提高。CA/（Ni+Ce+Zr）摩尔比为1的Ni-Ce-Zr/γ-MA催化剂在反应300 h内活性仅降低7%，并且没有明显积碳。表明催化剂在二氧化碳甲烷化反应中具有优异的反应稳定性和抗积碳性能。

关键词: 镍催化剂, 柠檬酸辅助, 混合金属氧化物, 二氧化碳, 甲烷化

Abstract:

Highly dispersed Ni-Ce-Zr mixed oxides supported on mesoporous γ-alumina (Ni-Ce-Zr/γ-MA) were prepared by a citric acid (CA)-assisted impregnation method and evaluated as catalysts for the methanation of CO2 with H2. The effects of the CA content of the reaction solution on the physicochemical properties and the catalytic performance of the Ni-Ce-Zr/γ-MA catalysts were investigated in detail. The addition of CA promoted the dispersion of the Ni-Ce-Zr oxide species on the γ-alumina surface and improved the interactions between the Ni oxide species and the support, resulting in the formation of homogeneously dispersed Ni nanoparticles in the γ-MA frameworks upon reduction with H2. The resulting Ni-Ce-Zr/γ-MA catalysts were highly active and showed almost 100% selectivity for CH4 during the methanation of CO2 at temperatures in the range of 150-400℃. Notably, the catalytic activity increased as the molar ratio of CA/(Ni+Ce+Zr) increased in the range of 0-2. This effect was most likely caused by the associated decrease in the Ni particle size and the improved electronic and structural properties of the Ni-Ce-ZrOx species. The results of a stability test for the Ni-Ce-Zr/γ-MA catalyst prepared with a CA/(Ni+Ce+Zr) molar ratio of 1.0 showed that there was only a 7% decrease in the CO2 conversion following a reaction time of 300 h at 300℃ with negligible coke deposition, indicating excellent catalytic stability and good anti-coking ability of these systems for the methanation of CO2.

Key words: Nickel catalyst, Citric acid-assistance, Mixed metal oxide, Carbon dioxide, Methanation