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