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

摘要

Dry reforming of methane (DRM), an energy intensive process, is one of the technologies that converts biogas (CH4 and CO_2) to syngas which can then be used as a starting material for various chemicals and liquid fuels. DRM usually occurs at temperatures between 600-900°C. Previous studies showed that high activity can be achieved at low temperature (450°C) using Pt-doped Ni/Mg catalyst supported on cerium-zirconium mixed oxide. The catalyst that gave the most desirable results from this study was the 0.16%Pt-1.34%Ni-l%Mg- Ce_(0.5)Zr_(0.4)O_2 catalyst. Our current work involves evaluating the role of Pt, Ni, and Mg on the catalyst and determining if all components are necessary. Elimination of unnecessary metals will lead to reduction in overall cost and synthesis time. Performance will be based on activity, selectivity, and stability results from the experimental DRM process. Two sets of supported metal catalysts series were prepared. A series contained no Ni metal; 0.16%Pt-0.5%Mg-Ce_(0.6)Zr_(0.4)O_2,0.16%Pt-1 %Mg-Ce_(0.6)Zr_(0.4)O_2, 0.16%Pt-2%Mg-Ce_(0.6)Zr_(0.4)O_2 while the other contained no Mg; 0.16%Pt-0.67%Ni-Ce_(0.6)Zr_(0.4)O_2,0.16%Pt-1.34%Ni-Ce_(0.6)Zr_(0.4)O_2,0.16%Pt-2.68%Ni-Ce_(0.6)Zr_(0.6)O_2.For the metal catalysts with no Mg, the conversion temperature decreased with increasing Ni loading. However, this trend was not observed for the H_2:CO ratio. The highest H_2:CO ratio was obtained using the 0.16%Pt- 1.34%Ni-Ce_(0.6)Zr_(0.6)O_2. For the metal catalysts with no nickel, the F_2:CO ratio decreased with increasing Mg loading. This trend was not the same for the conversion temperatures. The lowest temperature conversion was obtained from 0.16%Pt-0.5%Mg-Ce_(0.6)Zr_(0.4)O_2 catalyst.