Super-dry reforming of methane over surface oxygen mobility enhanced Ni/MgO-Ce/SBA-15 catalysts

Abstract

We developed a customized catalyst for the super-dry reforming of methane (S-DRM) reaction, designed to maximize CO₂ utilization compared to the conventional dry reforming of methane (DRM) reaction. The introduction of CeO₂ induced strong metal-support interactions (SMSI) in the Ni/MgO/SBA-15 catalyst, facilitating the high dispersion of Ni particles. Consequently, the crystallite size of metallic Ni (Ni⁰) was reduced, resulting in an increased number of Ni active sites. Furthermore, the incorporation of CeO₂ promoted the formation of oxygen vacancies (OVs), thereby enhancing CO₂ activation and improving the efficiency of the S-DRM reaction. As the CeO₂ content increased, the proportion of SBA-15 decreased, leading to a gradual reduction in surface area. However, at excessive CeO₂ content, a drastic decline in surface area was observed, which also resulted in a decrease in OVs that had previously shown an increasing trend with rising CeO₂ content. These changes could potentially diminish catalyst performance despite the enhanced SMSI. Therefore, maintaining an appropriate ratio of CeO₂:SBA-15 is crucial for maximizing catalyst performance and ensuring prolonged stability. The optimal catalyst, NMCS250, effectively balanced these factors, exhibiting high Ni dispersion, increased OVs, and basicity, which contributed to excellent catalytic activity and stability. Overall, NMCS250 was identified as the optimal catalyst, demonstrating superior catalytic performance due to its elevated Ni dispersion, increased oxygen vacancies, and basicity.