%0 Journal Article
%T Transformation of St£¿ber Silica Spheres to Hollow Hierarchical Single-Crystal ZSM-5 Zeolites with Encapsulated Metal Nanocatalysts for Selective Catalysis
%J -
%D 2019
%R https://doi.org/10.1021/acsami.9b00630
%X The activity of zeolite-supported nanocatalysts is dependent on both the dispersion, size, and location of metal nanoparticles around the zeolite and the size and pore structure of the zeolite. In this study, a synthetic approach was developed to encapsulate metal catalysts within hollow interiors of single-crystal ZSM-5. Briefly, St£¿ber silica spheres were synthesized and then transformed to single-crystal nano-ZSM-5 (Si/Al = 60), followed by growth of embedded metal nanoparticles and subsequently creation of a nanosized (30¨C50 nm shell thickness) hollow hierarchical zeolite structure. Metal nanoparticles such as Co, Cu, Cu¨CZn, Fe, and Ni can be supported on the inner wall of the hollow zeolite and the surrounding satellite mesopores, without any particles present on the external zeolite surface. When evaluated as a catalyst for the Fischer¨CTr£¿psch reaction, the [email protected] catalyst shows high activity, sintering and coking resistance (50% longer stability than [email protected]), and secondary cracking reactions in the acid sites in the ZSM-5 shell, which reduce C5+ hydrocarbon selectivity and increase smaller-chain hydrocarbon selectivity. In addition, when Pt was further deposited inside the hollow structure, shape-selective alkene hydrogenation was demonstrated. These configured nanoscale zeolite catalysts have potential applications for reactions that involve supported metal nanoparticle catalysis, shape selectivity, or secondary cracking reactions
%U https://pubs.acs.org/doi/10.1021/acsami.9b00630