Prior studies have reported the synthesis of naturally zoned zeolites where the exterior rim is enriched in either aluminum or silicon. Si/Al ratio) and assessing their effects on catalyst performance using the methanol-to-hydrocarbons (MTH) reaction. In this manuscript, we combine these approaches in catalyst design by focusing on the preparation of zeolites with tailored mesoscopic gradients in aluminum composition (i.e. There has also been growing interest in the development of methods to control aluminum distribution in zeolite frameworks on both a microscopic and mesoscopic level. Many synthetic approaches to optimize the physicochemical properties of zeolite catalysts focus on the design of hierarchical materials with nano-sized microporous domains that reduce diffusion limitations, thereby enhancing overall catalytic performance. Collectively, this study demonstrated that mesoscopic gradients in acid concentration via the design of core–shell and egg-shell zeolites significantly improve catalyst performance over conventional analogues for hydrocarbon upgrading. This inverse design of the egg-shell created pseudo nanosheets with total turnovers that were markedly higher than their homogeneous counterparts. Moreover, we prepared egg-shell configurations of each zeolite, and, comprised of an inert core and catalytically active shell. In comparison, prepared MFI core-shells ( ) showed similar enhancement in catalyst performance. Time-resolved acid titration of core and core–shell catalysts confirmed that the siliceous shell introduces a hydrophobic exterior that impacts molecular diffusion. Catalytic testing using the methanol-to-hydrocarbon (MTH) reaction showed that core–shell zeolites exhibit longer lifetimes, higher total turnovers, and an unexpected promotion of the aromatic cycle in the hydrocarbon pool mechanism. Our findings revealed that particles with ultrathin shells (<10 nm) have enhanced mass transport, characteristic of relatively smaller particles, compared to the corresponding ZSM-11 core.
CORE SHELL SERIES
A series of core–shell MEL-type zeolites were synthesized with catalytically active ZSM-11 cores and passivated silicalite-2 shells of varying thickness. Here, we systematically assessed the impact of mesoscopic gradients in acid site concentration, which has generally received little attention in the design of zeolite catalysts for hydrocarbon upgrading.
Historic District (1 point BD&C except Core and Shell, 2 points Core and Shell) Locate the project on an infill location in a historic district.Developing structure-performance relationships with the underlying goal of optimizing known zeolite catalysts involves the manipulation of their physicochemical properties. Landlord shall insure the Premises and Building, including Landlord supplied Core and Shell and Tenant Improvements as deemed necessary in Landlord's reasonable discretion. Healthcare (1–3 points) Requirements This credit includes requirements for product manufacturing as well as project teams.Warehouses and Distribution Centers (1–3 points).The energy upgrading of Kifissias Plaza, renamed into Green Plaza (is falling in the above-mentioned context, an investment totaling to approximately €7.000 while it was certified with LEED for Core and Shell at Gold Level in February 2017. The developer shall submit to the County Manager a statement listing all Energy Star qualified components prior to issuance of the Core and Shell Certificate of Occupancy.
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