Methane dry reforming over Ni/Mg-Al-O: On the significant promotional effects of rare earth Ce and Nd metal oxides

摘要

In this study, with the purpose to obtain more efficient catalysts for methane dry reforming, an Mg-Al-O support having excess MgO and higher alkalinity than pure MgAl2O4 spinel support have been designed and used to prepare Ni/Mg-Al-O catalysts. XRD has demonstrated that this support consists of both MgO and MgAl2O4 spinel phases. As a result, Ni/Mg-Al-O displays better reaction performance than Ni/MgAl2O4 and Ni/Al2O3 catalysts. With the promotion by Ce and Nd oxides, the Ni dispersion and the surface active oxygen amount can be significantly improved, which results in more active and stable catalysts with also significantly improved coking resistance. It is revealed that the active metallic Ni surface area, surface alkalinity and active oxygen abundance are the major factors deciding the reaction performance of the Ni/Mg-Al-O catalysts. Because of the optimal concerted action of these factors, Ni-Ce/Mg-Al-O, the sample promoted by ceria, displays the best reaction performance among all the catalysts.