FAU–LEV interzeolite conversion in fluoride media

Building Zeolites from Precrystallized Units: Nanoscale Architecture

“…Sano and co-workers reported the conversion of FAUi nto LEV (8 8-rings) in the presence of choline hydroxide.U nder these conditions,n oc rystalline phase was observed from amorphous aluminosilicate gels,thus undoubtedly proving the advantage of the use of the crystalline aluminosilicate precursor. [70] More recently,r esearchers at Chevron described as imilar synthesis method for preparing the LEV-type zeolite from FAUinfluoride media by using Nmethylquinuclidinium as an alternative OSDA. 9-12), and they functioned as excellent catalysts for the conversion of ethanol into light olefins (ETO), with high yields of ethylene and propylene (36 and 34 %, respectively).…”

“…Thes ame authors also reported the conversion of FAUi nto LEV in fluoride media by using 1-adamantanamine as an OSDA. [70] In this case,t he Si/Al molar ratios of the achieved LEV materials were higher than those obtained previously through the interzeolite transformation in alkaline conditions (Si/Al % 13-29). It was suggested that during the same morphological transformation, in this case FAUt oL EV,t he hydroxide and fluoride media resulted in different decomposition/dissolution rates.That is,the dissolution of the parent FAUwould be slower in fluoride media than in hydroxide media and, as aconsequence,the nucleation as well as crystallization would take place before the parent FAUw as completely consumed in the fluoride media.…”

“…It was suggested that during the same morphological transformation, in this case FAUt oL EV,t he hydroxide and fluoride media resulted in different decomposition/dissolution rates.That is,the dissolution of the parent FAUwould be slower in fluoride media than in hydroxide media and, as aconsequence,the nucleation as well as crystallization would take place before the parent FAUw as completely consumed in the fluoride media. [70] More recently,r esearchers at Chevron described as imilar synthesis method for preparing the LEV-type zeolite from FAUinfluoride media by using Nmethylquinuclidinium as an alternative OSDA. [71] Thealuminosilicate form of the AEI structure,SSZ-39, is another important small-pore zeolite that has received significant attention in the last few years for its potential applicability in DeNOx processes and methanol conversion reactions.…”

Topology reconstruction from FAU to MWW structure

“…Another type of ''zeolite to zeolite'' transformation, the so-called ''interzeolite http://dx.doi.org/10.1016/j.micromeso.2014.08.045 1387-1811/Ó 2014 Elsevier Inc. All rights reserved. conversion'' [19][20][21][22][23][24][25], proceeded as following sequence: starting zeolites ? amorphous phase (XRD) ?…”

Remarkable Charge Separation and Photocatalytic Efficiency Enhancement through Interconnection of TiO2 Nanoparticles by Hydrothermal Treatment

“…[24,25] This led to the discovery of hydrothermal conditions under which anatase and rutile are stable,w hereas less chemically stable TiO 2 -based compounds dissolve to recrystallize.Inthe present study,w et reated P25 under identical conditions to selectively dissolve the amorphous TiO 2 component of P25.…”