Origin of the Improved Performance in Lanthanum-doped Silica-supported Ni Catalysts

Abstract

Dry-reforming catalysts were prepared by supporting Ni nanoparticles (2–3 nm) on La-doped silica. These materials display higher activity and stability in low-temperature dry reforming (773 K) than Ni/SiO2 or Ni/La2O3. The La-doped silica-supported catalysts were found to have exclusively lanthanum silicate at their surface rather than La2O3 and/or SiO2. While an increasing amount of La was found to favor both CO2 adsorption capacity and strength, it also influenced the hydrogen adsorption strength on nickel particles significantly, as evidenced by H2 temperature-programmed desorption analysis. Finally, CH4 temperature-programmed reduction analysis revealed that the CH4 cracking threshold temperature varies in the order: Nibulk