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

采用浸渍法制备了一系列MTiO₃(M=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。

Methane reforming with carbon dioxide over the perovskite supported Ni catalysts

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.