载体形貌对Ni3Fe/CeO2催化剂甲烷干重整反应性能的影响

Effect of support morphology of Ni3Fe/CeO2 on catalytic performance for dry reforming of methane

  • 摘要: 通过改变水热法条件合成了不同形貌CeO2载体(棒状CeO2-R、立方体CeO2-C和多面体CeO2-P),并用浸渍法制备了Ni3Fe/CeO2催化剂,继而研究了不同载体形貌Ni3Fe/CeO2催化剂对其甲烷干重整反应性能的影响。采用X射线衍射、N2吸附-脱附、透射电镜、拉曼光谱、X射线光电子能谱、热重等对反应前后催化剂结构进行表征。结果表明,Ni3Fe/CeO2-R具有较大比表面积和较高的氧空位浓度,在甲烷干重整反应中表现出了优异的催化反应活性。800 ℃时,CH4和CO2的转化率分别为82%和91%,且反应10 h性能稳定并且其积炭石墨化程度较低。同时,通过CeO2-R载体氧空位对CO2活化,有效抑制了对亲氧性Fe物种的过度氧化行为,反应前后催化剂Ni3Fe合金结构保持稳定,具有良好的抗脱合金能力。

     

    Abstract: Different morphologies of CeO2 supports (including CeO2-R rod, CeO2-C cube, and CeO2-P polyhedron) were synthesized by hydrothermal method and were used to develop Ni3Fe/CeO2 catalysts by impregnation method for dry reforming of methane (DRM). The structures of the resultant catalysts before and after DRM were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry analysis. The results showed that Ni3Fe/CeO2-R exhibited good catalytic activity in DRM, where CH4 as well as CO2 conversion reached to 82% and 91%, respectively, at 800 ℃, owing to its large specific surface area and high oxygen vacancy concentration. The catalytic performance of Ni3Fe/CeO2-R was relatively stable and graphitic degree of coke deposition was low after 10 h. Meanwhile, the oxidative resistance of Ni3Fe/CeO2-R was improved as confirmed by the existence of stable Ni3Fe alloy after reaction, which mitigated the facile oxidation of more oxyphilic Fe species on the alloy by the promotion of CO2 activation on the vacancies of CeO2-R.

     

/

返回文章
返回