Merits of the CeLaCuO ternary oxide as promoter of the Ni/SBA-15 catalyst for the dry reforming of methane reaction

This work reports on the catalytic performance of 5 wt% Ni/SBA-15 catalysts promoted with different contents of CeLa10Cu metal-oxide (X = 0%, 10%, 20%, 30%, 40%) towards dry reforming of methane (DRM). The high surface area of SBA-15 allows the confinement of the Ni in its channels and improved its dispersion. The specific surface area of catalysts was found to be in the 182–307 m²/g range. Structural analysis (X-ray diffraction and Raman) of the catalysts showed that ceria-related cubic fluorite phase is only observed at the onset of 20% CeLa10Cu content and higher. Additionally, the Raman studies alongside with ²⁹Si solid state NMR demonstrated the promoter-support interactions through the formation of Ce–O–Si bond (Raman bands at 806 cm⁻¹ and 1065 cm⁻¹). The addition of CeLa10Cu promoter improved the reducibility and basicity of the catalyst, which was reflected in the time-on-stream (stability) tests performed on the reference catalyst (5% Ni/SBA-15) as well as on the 5% Ni/ 30% CeLa10Cu-SBA-15 (i.e. the best performing catalyst of this study). The latter catalyst demonstrated superior coke resistance in the long test runs (100 h). HR-TEM and XPS studies confirmed the formation of NiCu bimetallic alloy where Ni and Cu originating from the active metal and support, respectively; the latter affected the electronic structure and stabilized the catalyst during DRM reaction severe conditions. The CeLa10Cu promotion decreased carbon was formation (TGA analysis). The TGA analysis and Raman spectra of the spent catalysts showed that the 30% CeLa10Cu promotion exhibited the least carbon formation and of amorphous nature during the 100 h DRM. The low angle XRD showed some deterioration in the SBA-15 structure after 100 h DRM, whereas the SBA-15 structure was maintained after 12 h DRM.