Liming Xia,Bofeng Zhang,Gang Hou,Shuo Zhang,Li Wang,Guozhu Liu
Structured catalysts exhibit the advantages of high diffusion efficiency and low heat transfer resistance, which have attracted increasing attention to non-adiabatic gas–solid process. However, the metal-supported coating catalysts face the problems of weaker bond strength and severe sintering, especially under the conditions of large flow rate and high temperature. Herein, metal@Silicalite-1 structured catalysts with high adhesion and thermal stability were successfully prepared by hydroxylating the substrate with anatase. Rich surface Ti-OH significantly strengthened the adhesion stability of the zeolite coating. In propane dehydrogenation reaction, the optimized PtZn@S-1-15Ti showed a high specific activity of 49.6 mol C3H6 ·mol Pt −1 ·s −1 with propylene selectivity above 99% at 600°C. The introduction of anatase accelerated the aggregation of silicon sources and induced nucleation with growth content of zeolite increased by 3.6 times. It breaks the inherent contradiction between high loading amount and strong binding ability of coated catalysts, which broadens the avenues for industrial applications.
Liming Xia,Bofeng Zhang,Gang Hou,Li Wang,Sibao Liu,Guozhu Liu
Structured catalysts coatings exhibit excellent performance on non-adiabatic gas–solid process, deriving from their enhanced heat and mass transfer properties. However, the coating catalysts prepared by traditional hydrothermal method of zeolite encapsulating noble metal are prone to spalling, especially under conditions of large flow rate and high temperature. Herein, we prepared PtZn clusters encapsulated in silicalite-1 zeolite coating on stainless steel with high bonding strength by an improved in situ growth method. The optimized catalyst exhibited ultra-thin, uniform, continuous, and high degree of crosslinking, thereby enhancing mass transfer and thermal stability. In propane dehydrogenation reaction, the optimized PtZn@S-1-R showed a high specific activity of 14.7 mol C 3 H 6 $$ {\mathrm{mol}}_{{\mathrm{C}}_3{\mathrm{H}}_6} $$ mol Pt −1 s −1 and a propylene selectivity above 99% at 600°C with a high weight hourly space velocity of 120 h −1 . The metal-encapsulated zeolite coating catalysts broaden the application avenue for heterogeneous catalysis with great application prospects.
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