Methane Dry Reforming over Ce/Zr- and La-modified SBA-15/Ni Catalysts

Abstract

Nickel-based catalysts supported on mesoporous SBA-15 were synthesized and evaluated for dry methane reforming as a route for simultaneous utilization of CH₄ and CO₂. To enhance catalyst stability and coke resistance, Ce–Zr mixed oxides and La were introduced either by post-synthesis impregnation or by pre-modification of the SBA-15 support. Textural and structural characterization revealed that pre-modified catalysts possess higher specific surface areas and improved Ni dispersion compared to post-modified analogues. All catalysts exhibited high initial activity at 800 °C with CH₄ and CO₂ conversions exceeding 80%. However, significant differences in stability were observed. The unmodified SBA-15/Ni catalyst showed a pronounced gap between CH₄ and CO₂ conversions and H₂/CO ratios below 1, indicating intensive coke formation and reverse water–gas shift activity. Incorporation of Ce–Zr suppressed deactivation by enhancing redox properties and CO₂ activation, while La addition further improved stability through carbonate formation and carbon gasification. The highest resistance to deactivation was achieved for the SBA-15/Ce/Zr/La/Ni catalyst prepared via pre-modification, which exhibited minimal conversion loss, near-stoichiometric H₂/CO ratios, and the smallest conversion gap. These results demonstrate that controlled incorporation of redox-active promoters and optimized preparation strategy are key factors in designing stable Ni/SBA-15 catalysts for DRM.