(115e) Developing New Approaches to Address Old Problems in Zeolite Catalysis

A ubiquitous challenge for engineering zeolite catalysts is the mass transport limitations imposed by their small pores, which limit catalyst lifetime and often compromise their efficiency in commercial reactions. One solution to circumvent this issue is to design nanosized or hierarchical zeolites with higher surface area for greater access to pores and markedly shorter dimensions for improved diffusion within pores; however, conventional synthesis methods to generate these materials are nontrivial, limited mostly to ZSM-5 materials, and involve costly procedures that result in low yields with restricted acid site density. This presentation will focus on recent efforts in our group to design finned zeolites as a new class of heterogeneous catalysts with dramatically improved mass transport properties. The introduction of fins involves a facile secondary growth procedure that places small, epitaxially-grown protrusions on the surfaces of seed crystals. Our findings reveal that these features effectively convert large crystals into pseudo nanoparticles with a catalytic performance equivalent to particles with sizes comparable to that of the fin (20 – 50 nm) – thus allowing materials off the shelf to be significantly improved by a versatile approach that circumvents the challenges and shortcomings of other hierarchical zeolite syntheses. The preparation of finned zeolites has been demonstrated for 3-dimensional (MFI, MEL, CHA), 2-dimensional (FER), and 1-dimensional (MTT, MOR, MTW) frameworks prepared in house as well as select commercial samples. This talk will also show how we have demonstrated the ability to introduce heteroatoms in fins as well as controlled Si/Al ratios between the seed and fin to enhance catalyst performance – analogous to zoned and core-shell zeolites. Our findings show how these novel materials exhibit exceptional catalytic performance compared to conventional analogues. Here we will provide an overview of catalyst synthesis, characterization, and testing to assess their performance using benchmark reactions for hydrocarbon upgrading.