Heterobimetallic zeolites: Synthesis, characterization, and applications

Heterobimetallic zeolites, where framework aluminum is replaced by other elements such as B, Ga, In, Sn etc, are generally synthesized directly from precursors. Such substitution impacts zeolites catalytic properties and durability. Here, we report a direct solution exchange method to partially substitute aluminum in metal exchanged zeolites. The methods simplicity method enables tuning of zeolites for catalytic reactions. For example, partial substitution of framework aluminum in Cu-ZSM-5 with Fe³⁺ results in Cu-FeZSM-5 materials. Our studies show that Cu-FeZSM-5 can effectively reduce 80% NO_x under fast NH₃-SCR conditions at 150°C while Cu-ZSM-5 can only reduce 30% NO_x. Among other zeolites, we have synthesized partial iron substitution of Cu-zeolite-Y and Cu- zeolites-β. The synthesis and characterization of zeolites and their ability to reduce NO_x will be presented. We will also present our results on the impact of framework aluminum substitution on the product distribution when these zeolites are employed in alkane conversion.