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

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。

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 metalsupport 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.