物理化学学报 >> 2004, Vol. 20 >> Issue (01): 76-80.doi: 10.3866/PKU.WHXB20040116

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La2O3 和CeO2对CH4-CO2重整Ni/MgO催化剂结构和性能的影响

陈吉祥;邱业君;张继炎;苏万华   

  1. 天津大学化工学院催化科学与工程系,天津 300072; 天津大学一碳化学与化工国家重点实验室,天津 300072; 天津大学内燃机燃烧学国家重点实验室,天津 300072
  • 收稿日期:2003-05-28 修回日期:2003-08-14 发布日期:2004-01-15
  • 通讯作者: 陈吉祥 E-mail:jxchen@tju.edu.cn

Influence of La2O3 and CeO2 Promoters on Physico-chemical Properties and Catalytic Performance of Ni/MgO Catalyst in Methane Reforming with Carbon Dioxide

Chen Ji-Xiang;Qiu Ye-Jun;Zhang Ji-Yan;Su Wan-Hua   

  1. Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University; State Key Laboratory of C1 Chemistry and Chemical Technology; National Engine Combustion Laboratory, Tianjin University, Tianjin 300072
  • Received:2003-05-28 Revised:2003-08-14 Published:2004-01-15
  • Contact: Chen Ji-Xiang E-mail:jxchen@tju.edu.cn

摘要: 采用共沉淀方法制备了NiO-MgO、NiO-La2O3-MgO、NiO-CeO2-MgO三种催化剂,用BET、XRD、TPR、XPS、TG及活性评价等方法考察了La2O3、CeO2助剂对NiO-MgO物化性质和CH4-CO2重整反应性能的影响.实验结果表明,三种催化剂中镍物种以镍镁固溶体形式存在.与NiO-MgO相比, NiO-La2O3-MgO、NiO-CeO2-MgO具有较高比表面积,且其镍物种可还原能力有所增强, NiO-CeO2-MgO尤为明显. La2O3、CeO2均在一定程度上改善了NiO-MgO的CH4-CO2重整反应性能,提高了镍晶粒的抗烧结能力.但二者的作用机制有所差异, La2O3和CeO2分别主要作为结构助剂和电子助剂发挥作用.

关键词: 甲烷-二氧化碳重整反应, 镍镁固溶体, 氧化铈, 氧化镧, 烧结, 积碳

Abstract: Three catalysts, NiO-MgO, NiO-La2O3-MgO and NiO-CeO2-MgO containing 10%(w) Ni were prepared by the co-precipitation method. The effects of La2O3 and CeO2 on physico-chemical properties and catalytic performance of NiO-MgO catalysts were studied by means of BET, XRD, TPR, XPS, TG and reaction activity evaluation. It was found that NiO formed a nickel-magnesia solid solution with MgO, and La2O3 and CeO2 promoters improved the resistance to sintering of the nickel-magnesia solid solution, which was attributed to the higher specific surface area and smaller size of crystallites of the Nickel-magnesia solid solution. Besides, La2O3 and CeO2 could promote reduction of nickel species in nickel-magnesia solid solution, especially CeO2. Under reaction conditions of CH4/CO2=1(molar ratio), 0.1 MPa, 1023 K and 1073 K, 18 L•g-1•h-1, NiO-La2O3-MgO and NiO-CeO2-MgO showed higher activity than NiO-MgO. However, the three catalysts had similar activity at 1123 K because the reaction was close to the thermodynamic equilibrium under these reaction conditions. La2O3 and CeO2 act as a structural promoter and an electronic promoter respectively to improve the properties of NiO-MgO.

Key words: Methane reforming with carbon dioxide, Nickel-magnesian solid solution