Key Words:Direct conversion of Al-SBA-15; Nano-sized ZSM-5; Hierarchical structure; Monolithic morphology; Characterization

Abstract:This work presents a facile method for synthesizing monolithic ZSM-5 nanoparticle aggregates (ZNA) by directly converting the ordered mesoporous material Al-SBA-15 under low solvent content conditions. The effects of crystallization temperature, time, and the structure-directing agents (SDAs) content on the textural properties and on the crystallinity of the final product were investigated. The crystal growth was physically confined to a nano-scale space surrounded by chemically inert units previously formed through the controllable decomposition of P123 micelles. The resulting nanoparticles exhibit uniform size in the range of 20-40 nm. Moreover, ZNA has a monolithic morphology of several micrometers in size, closely resembling that of raw Al-SBA-15, allowing the avoidance of a high-speed centrifugal separation process. The location of nanoparticles inside ZNA bulk particles can be mainly restricted to replicating the Al-SBA-15 walls by slowing down the inorganic species consumption process, and consequently, forming a visibly ordered mesostructure. (C) 2016 Elsevier B.V. All rights reserved.

Volume:695

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Translation or Not:no