Nanostructured Pt- and Ni-based catalysts for CO2-reforming of methane

The effect of using a nanofibrous Al2O3 as support for Ni-based catalysts, modified with Pt, for the dry reforming of methane (DRM) was studied. Monometallic (Ni and Pt) and bimetallic (PtNi) supported catalysts were synthesized, characterized (XRD, TEM, XPS, Raman and Elemental Analysis) and tested under DRM conditions. A monometallic Pt catalyst supported on a commercial alumina was also prepared and studied for comparative purposes. Characterization results showed that the nanofibrous alumina allowed nanostructured systems with Pt and Ni particles well dispersed, avoiding metal sintering. Additionally, Pt addition promoted the formation of NiO, instead of NiAl2O4, and facilitated its reduction to Ni0 during the catalysts activation. It was also observed that the average size of Ni0 particles decreased with increasing Pt content. Activity tests demonstrated that Pt presence and the use of the nanofibrous support in Ni catalysts improve CH4 and CO2 conversions, reaching values close to equilibrium. Moreover, Pt inhibits coke deposition and reduces the operation temperature. From stability tests it can be concluded that Pt enhances the stability of Ni-based catalysts for DRM.