(558br) Effect of Impregnation Strategy on the Performance of Pt/Ceria-Zirconia Low Temperature Reforming Catalysts

Catalyst preparation method can greatly impact performance. In view of this, our present work is centered on investigating the effect of metal impregnation strategy and particle size on the performance of complex dry reforming catalyst. The specific focus is on how the metal impregnation strategy and particle size influence the metal interface and metal-support interaction. Previous work by our research group investigated the effect of metal loadings on a set of low temperature reforming catalysts synthesized using the co-impregnation (incipient wetness) of the metals on the catalyst support (Ce_0.6Zr_0.4O₂ (CZO)). The best performing catalysts which all contained Pt (0.16 wt%) were 2.7Ni-CZO _, 0.50Mg-CZO and 2.7Ni-0.50Mg-CZO samples.

In our present work, the above stated samples were synthesized by either directly dissolving the Pt precursor (e.g. 2.7Ni-CZO-S) or using Pt nanoparticles (3.4 nm) obtained from colloidal synthesis involving a capping agent (PVP) (e.g. 2.7Ni-CZO-P). The Pt was impregnated alongside Ni/Mg onto the support using sequential impregnation. The samples containing the 3.4 nm Pt nanoparticles were washed to remove organics and some of these samples was further subjected to calcination (e.g 2.7Ni-CZO-C). The catalyst samples were characterized using powdered X-ray diffraction, N₂-Physisorption, temperature-programmed reduction (TPR), and temperature programmed oxidation (TPO). Temperature-programmed experiments were performed to evaluate the activity of the catalysts for dry reforming. The results obtained indicate that conversion for the Ni containing samples follow the trend; 2.7Ni-CZO-P< 2.7Ni-CZO-S < 2.7Ni-CZO-C< 2.7Ni-CZO. Higher reactant conversion and H₂:CO product ratio were obtained with the 0.50Mg-CZO sample in comparison to the 0.50Mg-CZO-S. This work will provide relevant knowledge on how the properties and structures of catalyst materials can be tuned to achieve optimal catalyst performance.