钙钛矿型氧化物负载Ni催化剂上甲烷二氧化碳重整反应研究

Methane reforming with carbon dioxide over the perovskite supported Ni catalysts

  • 摘要: 采用浸渍法制备了一系列MTiO3M=Mg、Ca、Sr、Ba)钙钛矿型氧化物负载的Ni催化剂(Ni的负载量为5%,质量分数),通过XRD、氮吸附、H2-TPR、CO2-TPD、XPS和TG等技术对催化剂进行了表征,对其甲烷二氧化碳重整反应的催化性能进行了研究。结果表明,M为不同碱土金属时,催化剂上金属载体相互作用、活性组分的表面原子浓度以及催化剂晶格氧的流动性都发生了变化。Ni/CaTiO3催化剂上金属载体相互作用较强,还原出的活性组分Ni的含量较多,晶格氧流动性较高,因而具有较好的催化性能。SrTiO3载体颗粒粒径较大,Ni/SrTiO3催化剂上Ni的分散度不高,金属载体的相互作用较弱,表面Ni原子相对含量较低,晶格氧的流动性较差,其甲烷二氧化碳重整反应活性也最低。

     

    Abstract: A series of MTiO3 (M=Mg, Ca, Sr, Ba) supported Ni catalysts (with a Ni loading of 5%) for methane reforming with carbon dioxide (DRM) were prepared by the impregnation method. The Ni/MTiO3 catalysts were characterized by XRD, N2 sorption, H2-TPR, CO2-TPD, XPS and TG; the effect of alkaline earth metals (M) on the catalytic performance of Ni/MTiO3 in the DRM was then investigated. The results indicate that the metal-support interaction, the surface Ni atomic concentration and the mobility of lattice oxygen species on the Ni/MTiO3 catalysts are related to the alkaline earth metal M used in the MTiO3 supports. The Ni/CaTiO3 catalyst shows superior performance in DRM to other catalysts, which is ascribed to the strong metal-support interaction, large amount of reduced active Ni and relatively high mobility of lattice oxygen species. In contrast, the SrTiO3 support has a relatively large particle size, leading to poor Ni dispersion on the Ni/SrTiO3 catalyst as well as weak metal-support interaction, low lattice oxygen mobility, and less surface active Ni atoms; as a result, the Ni/SrTiO3 catalyst exhibits relatively poor performance in DRM.

     

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