(21d) The Effect of Nickel and Magnesium Loadings on the Activity, Selectivity and Stability for Catalytic Dry Reforming of Biogas Using Pt/Cerium-Zirconium Oxide Catalyst

Biogas containing methane (CH₄) and carbon dioxide (CO₂) can be converted to syngas, which is an important chemical feedstock for the generation of various important chemicals and liquid fuels. The reforming of CH₄ with CO₂ is an attractive route to upgrade biogas to syngas because it uses two important greenhouse gases and generates a lower H₂:CO ratio compared to steam reforming. The CO₂ reforming of CH₄ is an energy intensive process that typically requires suitable catalysts operating at high operating temperatures (600^°C-900^°C). In this work, we studied the low temperature CO₂ reforming of CH₄ using a series of Pt/cerium-zirconium oxide catalysts doped with various weight percent loadings of nickel (Ni) or magnesium (Mg). Reaction studies show that increasing nickel loading from 0.67wt% to 2.68wt% in the Pt/cerium-zirconium oxide catalyst lowered reduction and CH₄ conversion temperatures. In contrast, increasing magnesium loading from 0.5wt% to 2.0wt% in the Pt/cerium-zirconium oxide catalyst resulted in an increase of the reduction and CH₄ conversion temperatures. The H₂:CO ratios decreased with increasing nickel loadings but increased with increasing magnesium loading. This study shows that a lower Pt/Ni ratio in the catalyst combination favors CH₄ conversion but not selectivity while a higher Pt/Mg ratio favors CH₄ conversion and product selectivity. Due to the performance achieved at low temperatures (400^°C-500^°C) in this study, these catalysts has the potential to be employed in intensified processes at low to moderate temperatures.