物理化学学报 >> 2015, Vol. 31 >> Issue (4): 757-763.doi: 10.3866/PKU.WHXB201501091

催化和表面科学 上一篇    下一篇

Al2O3改性CuO/Fe2O3催化剂水煤气变换反应性能

林性贻, 殷玲, 范言语, 陈崇启   

  1. 福州大学化肥催化剂国家工程研究中心, 福州350002
  • 收稿日期:2014-11-13 修回日期:2015-01-05 发布日期:2015-04-03
  • 通讯作者: 林性贻 E-mail:linxingyi@fzu.edu.cn
  • 基金资助:

    国家自然科学基金(21346007)资助项目

Performance of Al2O3-Modified CuO/Fe2O3 Catalysts in the Water-Gas Shift Reaction

LIN Xing-Yi, YIN Ling, FAN Yan-Yu, CHEN Chong-Qi   

  1. National Engineering Research Center of Chemical Fertilizer Catalysts, Fuzhou University, Fuzhou 350002, P. R. China
  • Received:2014-11-13 Revised:2015-01-05 Published:2015-04-03
  • Contact: LIN Xing-Yi E-mail:linxingyi@fzu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21346007).

摘要:

采用分步共沉淀法制备了不同Al2O3含量(0%-15% (w))的CuO/Fe2O3催化剂, 并进行水煤气变换反应(WGSR)评价测试. 制得的催化剂中含有复合物CuFe2O4, 其晶粒尺寸, 氧化还原性质和表面Cu分散通过相应表征手段加以研究. X 射线粉末衍射(XRD), 拉曼(Raman)光谱, N2物理吸附, N2O分解和CO2程序升温脱附(CO2-TPD)等表征技术说明适量Al2O3的加入可以促进尖晶石CuFe2O4发生由四方相向立方相的转变, 阻止催化剂中Cu烧结, 增大表面Cu分散, 增加弱碱性位点的数量. 此外, 采用H2程序升温还原(H2-TPR)技术探究改性的CuO/Fe2O3催化剂的还原性能. 关联结果发现, Al2O3掺杂在增大铜物种的耗氢量, 降低其还原温度方面起着重要的作用. 即Al2O3的添加促进CuO/Fe2O3催化剂中铜铁物种之间的协同作用. 结合活性测试和表征结果,适量的Al2O3 (10%(w))改性的催化剂具有较小的Cu颗粒尺寸、较大的Cu分散、较强的还原性能、较多数量的弱碱性位点, 因此具有更好的初始活性和热稳定性.

关键词: CuFe2O4, 水煤气变换反应, Al2O3改性, Cu分散, 弱碱性位点, N2O分解

Abstract:

The water-gas shift reaction (WGSR) has been carried out over CuO/Fe2O3 catalysts modified by different loadings of Al2O3 (0%-15% (w)), prepared by a stepwise co-precipitation method. Composite mixture CuFe2O4 was produced, and the crystalline size, redox property, and surface metallic Cu dispersion were manipulated. The appropriate introduction of Al2O3 can promote the phase transition of spinel CuFe2O4 from tetragonal to cubic, inhibit aggregation of Cu-crystallite, improve Cu dispersion, and increase the amount of weak basic sites, as confirmed using powder X-ray diffraction (XRD), Raman spectroscopy, N2 physisorption, N2O decomposition, and temperature-programmed desorption of carbon dioxide (CO2-TPD) techniques. In addition, a temperature-programmed reduction of hydrogen (H2-TPR) technique was used to investigate the reducibility of the modified CuO/Fe2O3 catalysts. It was found that the Al2O3-doping plays an important role in increasing the hydrogen consumption of the copper species, and decreasing reduction temperature. This means that the Al2O3 can promote a synergistic interaction between the copper and iron species in the CuO/Fe2O3 catalysts. Overall, the Al2O3-modified catalyst (10%(w)) has a smaller Cu particle size, better Cu dispersion, greater reducibility, and larger amount of weak basic sites, resulting in a much higher initial catalytic activity and better thermal stability.

Key words: CuFe2O4, Water-gas shift reaction, Al2O3-modification, Cu dispersion, Weak basic site, N2O decomposition

MSC2000: 

  • O643.3