Reforming of Methane with Carbon Dioxide over Pt/ZrO2/Al2O3 Catalysts

The kinetics of CO2 reforming of methane was studied over Pt supported on Al2O3, ZrO2, and x% ZrO2/Al2O3 (1≤x≤20 wt%), and the catalysts were characterized using different techniques. The influence of the support on the catalyst activity and carbon deposition resistivity was markedly different in each case. Although the Pt/Al2O3 catalyst deactivated significantly within 20 h onstream at 1073 K, zirconia-containing catalysts exhibited much higher stability even after 60 h onstream. Thermogravimetric analysis results showed that the amount of carbon on Pt/Al2O3 is much larger than on Pt/ZrO2. Temperature-programmed reduction, CO chemisorption, and Fourier transform infrared of CO results provided evidence of metal–support interactions on zirconia-containing catalysts, indicating that the suppression of carbon deposition over these systems is probably due to Pt–Zrn+ interactions. A reaction mechanism was proposed involving two different pathways: CH4 decomposition on metal particles and CO2 activation on the support. A kinetic model based on this dual mechanism successfully correlated the experimental data.