(544cn) Mixed Metal Small Pore Zeolites: Synthesis, Characterization and Catalytic Testing

Metal-exchanged zeolites have found a range of industrial applications due to the imparting of d-block metal functionality into the uniform confined spaces of the zeolite micropores. As an example, copper-exchanged high-silica chabazite has emerged as the industrial catalyst of choice in the selective catalytic reduction of NO. However, while there have been many studies of single metals exchanged into zeolites, the case of mixed transition metal zeolites obtained is very sparse. This work will outline our initial efforts to exchange two metals into SSZ-39 and SSZ-13 and their properties.

SSZ-13 samples with Si/Al gel ratios of 5, 15 and 25 were synthesized and tested for ion-exchange. Before ion exchanges involving two metals were studied SSZ-13 exchange capabilities of nickel and cobalt were explored. Nickel ion-exchange results showed uptake with Ni/Al ratios of 0.026, 0.011 and 0.017 for the SSZ-13 samples indicating an inability to load nickel(II) into the zeolite under the conditions used. On the contrary, cobalt exchange was much more promising, with efficiencies comparable to prior literature for copper exchange of SSZ-13. The Co/Al ratios were found to be 0.247, 0.303 and 0.086 for SSZ-13 samples with Si/Al gel ratios of 5, 15 and 25, respectively. Current work is making a series of mixed Co/Cu samples: 100% Cu-SSZ-13, 75-25% CuCo-SSZ-13, 50-50% Cu-Co, 25-75% CuCo-SSZ-13 and 100% Co-SSZ-13. Preliminary results indicate it is possible to make samples containing both Cu and Co as evidenced from elemental analysis and UV-Vis spectroscopy.

Ongoing work is exploring these materials in more detail. Results that will be presented in the talk will include UV-Vis studies to attempt to elucidate how the metal coordination varies in the binary system. This will be correlated with synchrotron X-ray diffraction studies as well as neutron diffraction. Ongoing work is also testing these materials for the selective catalytic reduction of NO to compare those findings to the wealth of literature on copper SSZ-13.