(308c) Catalyst Design for Microwave Assisted Methane Dehydroaromatization
The catalyst for methane DHA is typically composed of metal nanoparticles dispersed in zeolites. In these catalyst systems, parameters including zeolite particle size, the concentration of Brønsted acid sites, speciation and dispersion of metals, and the nature of the metal can be expected to not only affect the catalytic reactivity but also to influence the ability of the catalyst to absorb and interact with microwave radiation. The main objective of our study is hence to obtain an improved understanding of what gives metal/zeolite-based catalyst higher microwave sensitivity. Towards this goal, we synthesized carefully defined metal/ZSM-5 catalysts to individually vary the size and Si/Al ratio of the zeolite ZSM-5, as well as speciation and type of metal in the catalyst. We find that incorporating more Al into the ZSM-5 framework increases the microwave sensitivity, while the size of ZSM-5 has a comparatively small effect. On the metal side, Fe-ZSM-5 was prepared via three different synthetic approaches to control metal dispersion and speciation. We find that both metal speciation and metal loading have significant impact on microwave sensitivity. Further studies regarding the nature of the metal are currently on-going. The observed effects will be presented and discussed in detail in the presentation.
Overall, through these studies, we aim to develop a fundamental understanding of metal/zeolite catalysts in microwave catalysis as a basis for rational catalyst design for microwave-assisted methane DHA.