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

Abstract

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.