物理化学学报 >> 2016, Vol. 32 >> Issue (7): 1801-1809.doi: 10.3866/PKU.WHXB201604081

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Zr掺杂对PdO/Ce1-xPdxO2-δ催化剂CO和CH4催化氧化的影响

贾永昌,王树元,孟涟,鲁继青,罗孟飞*()   

  • 收稿日期:2015-12-29 发布日期:2016-07-08
  • 通讯作者: 罗孟飞 E-mail:mengfeiluo@zjun.cn
  • 基金资助:
    国家自然科学基金(21203167);国家自然科学基金(21173195);浙江省公共应用技术项目(2013C31049)

Effects of Zr Addition on CO and CH4 Catalytic Oxidation over PdO/PdO/Ce1-xPdxO2-δ Catalyst

Yong-Chang JIA,Shu-Yuan WANG,Lian MENG,Ji-Qing LU,Meng-Fei LUO*()   

  • Received:2015-12-29 Published:2016-07-08
  • Contact: Meng-Fei LUO E-mail:mengfeiluo@zjun.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21203167);The project was supported by the National Natural Science Foundation of China(21173195);Zhejiang Province Public Technology Applied Research Projects, China(2013C31049)

摘要:

采用溶液燃烧法制备出PdO/PdO/Ce1-xPdxO2-δ (PdO/CP)和PdO/Ce1-x-yPdxZryO2-δ (PdO/CPZ)催化剂,通过硝酸处理去除催化剂表面的PdO物种得到对应的PdO/Ce1-xPdxO2-δ (CP)和Ce1-x-yPdxZryO2-δ (CPZ)催化剂。考究四种催化剂(PdO/CP、PdO/CPZ、CP、CPZ)对CO和CH4的氧化活性,并计算得出表面PdO和Pdn+物种的转化频率(TOF)。结果表明Zr的添加对PdO催化剂上CO和CH4的催化氧化活性具有不同的影响。Zr的添加对PdO/CPZ和CPZ催化剂的CO催化活性具有明显的促进作用,前者归因于PdO/CPZ催化剂表面生成了更小颗粒的PdO粒子,后者归因于CPZ催化剂中含有更多的氧空位。对于CH4的催化氧化,Pdn+物种起到关键的作用。由于Zr的掺杂导致CeO2的晶格中Pd物种的含量减少,致使PdO/CPZ催化剂和CPZ催化剂对CH4氧化活性的降低。

关键词: 铈, 氧化钯, 氧空位, CO氧化, CH4氧化

Abstract:

PdO/PdO/Ce1-xPdxO2-δ (PdO/CP) and PdO/Ce1-x-yPdxZryO2-δ (PdO/CPZ) catalysts were prepared via a solution combustion method. The corresponding PdO/Ce1-xPdxO2-δ (CP) and Ce1-x-yPdxZryO2-δ (CPZ) catalysts were obtained by nitric acid treatment of the PdO/CP and PdO/CPZ catalysts to remove the surface PdO species. These catalysts were tested for CO and CH4 catalytic oxidation. The turnover frequencies (TOFs) of surface PdO and Pdn+ cations in the CP and CPZ solid solutions were calculated. The results showed that Zr addition in the PdO/CP catalyst had very different effects on CO and CH4 oxidation. A significant improvement in CO oxidation activity was observed over the Zr-containing catalysts; this could be related to the formation of smaller PdO particles on the surface of the PdO/CPZ catalyst and a higher oxygen vacancy concentration in the CPZ solid solution. For CH4 oxidation, Pdn + cations in the solid solution play a key role in the catalytic oxidation process. The penetration of Zr4+ cations into the CeO2 lattice decreased the amount of Pd2+ cations in the CPZ solid solution and thus inhibited the activities of the Zr-containing catalysts (PdO/CPZ and CPZ) for CH4 oxidation.

Key words: Zr, PdO, Oxygen vacancy, CO oxidation, CH4 oxidation

MSC2000: 

  • O643