Lanthanide oxide modified nickel supported on mesoporous silica catalysts for dry reforming of methane

Addition of rare earth oxide, especially lanthanide oxide, was regarded as a promising strategy to improve the carbon resistance for Nickel-based catalysts in dry reforming of methane (DRM). In this work, Nickel-based catalysts containing lanthanide oxides (NiLa/SiO₂, NiCe/SiO₂, NiSm/SiO₂, and NiGd/SiO₂) were prepared and employed to catalyze DRM. Lanthanide oxide affected the formation of Ni nanoparticles in different size. In NiLa/SiO₂ and NiCe/SiO₂, Ni nanoparticles maintained relatively small size (4 nm), while in NiSm/SiO₂ and NiGd/SiO₂, nickel particles were in large size (8 nm). NiLa/SiO₂ and NiCe/SiO₂ exhibited better stability than the other two catalysts, with CH₄ conversion decreasing from 64.6 to 57.6% and 61.6 to 60.3%, respectively in 10 h on stream. The kinetic study confirmed that adding lanthanide oxide significantly affected the activation energy of CH₄ dissociation and CO₂ dissociation. Compared to monometallic Ni/SiO₂, the presence of Sm and Gd suppressed CO₂ dissociation, and introduction of Ce and La effectively promoted CO₂ dissociation. These characters contributed to the higher carbon resistance and good stability for NiLa/SiO₂ and NiCe/SiO₂ catalysts in DRM reaction.