CO2 reforming of methane over highly active La-promoted Ni supported on SBA-15 catalysts: mechanism and kinetic modelling

Abstract

Various Ni catalysts were synthesized by combining a high surface area SBA-15 support, a novel preparation method using an oleic acid precursor to obtain highly dispersed and small Ni particles, and the basic property of La. The activity test shows that the La-promoted Ni/SBA-15 catalyst has much higher catalytic activity and stability than unpromoted Ni/SBA-15 catalysts in the CO₂ (dry) reforming of methane (DRM) reaction due to the crucial role of La to simultaneously adsorb CO₂ and remove deposited carbon from the Ni metal surface. The optimization of La content shows that only a small amount of La around 1 wt% is necessary to achieve the best catalytic performance. The reaction mechanism was then proposed and kinetic modeling (for pilot scale) was performed to find the rate-determining step (RDS) in the DRM reaction for this 1% La-promoted Ni/SBA-15 catalyst. The obtained fitting result shows that CH₄ decomposition is the RDS for this catalyst with an apparent activation energy of around 40.8 kJ mol⁻¹ which is similar to the activation energies reported for common Ni-based supported catalysts.