(696d) Isolating the Effect of Metal Composition on Bi-Functional Pt/Ceria-Zirconia Low Temperature Reforming Catalysts | AIChE

(696d) Isolating the Effect of Metal Composition on Bi-Functional Pt/Ceria-Zirconia Low Temperature Reforming Catalysts


Sokefun, Y. O. - Presenter, University of South Florida
Yung, M. M., National Renewable Energy Laboratory
Joseph, B., University of South Florida
Kuhn, J., University of South Florida
The harmful impact of greenhouse gas emissions and the need to protect the environment from these impacts has geared research on renewable energy sources. Following this trend, the focus of our research has been on the synthesis of improved catalytic materials for the conversion of biogas sourced methane and carbon dioxide to syngas using low-temperature reforming materials. Catalyst materials consisting of ceria-zirconia (CZO) support, Pt (0.16wt%), Ni (0.67-2.68 wt%) and/or Mg (0.5-2.0 wt%) were prepared using the incipient wetness method. Powder X-ray diffraction was used to identify crystal structures of the materials and the diffraction patterns representing the cubic-fluorite phase of ceria-zirconia was observed. The presence of the cubic-fluorite phase was supported by the Raman spectroscopy, which showed bands belonging to the F2g vibration bands of fluorite ceria. CO2 desorption studies showed an increase in the amount of CO2 desorbed from 21 to 30 µmol of CO2/gcat in the 0.16wt%Pt-2.7wt%Ni-CZO upon the addition of Mg. The reducibility of the Pt-Ni-CZO samples increased with increasing Ni content and CH4 conversion correlated to sample reducibility. Increasing Mg amount resulted in a decrease in CH4 conversion but helped improve H2:CO. The increase in basicity with Mg addition was confirmed by CO2-TPD FTIR studies which showed the Pt-Mg-CZO sample having stronger carbonates bands at higher temperatures in comparison to the Pt-Ni-CZO sample. The detection of coke (5.5 X 10-4 g/gcat.h) over the 0.16wt%Pt-2.7wt%Ni-CZO and its absence with the addition of Mg reveal that both Ni and Mg need to be incorporated into the catalyst formulation to obtain a balance between catalyst activity, selectivity, and stability. Our study on the effects of the metal contents provide key insights into optimal catalyst design and indicate the possibility of designing catalyst materials for intensified processes, due to the low-temperature activity and stability and reasonable selectivity.