Hydrothermal Conversion of Titanated FAU to AEI Zeolite and Its Enhanced Catalytic Performance for NO<SUB><I>x</I> </SUB> Reduction

On the key role of aluminium and other heteroatoms during interzeolite conversion synthesis

“…Zones pioneered the eld and reported the use of calcined boron-beta zeolite as the source of both boron and silicon in the formation of [B]CON (SSZ-33) as early as 1994. 185 More recently, IZC synthesis of zeolites containing Sn, [186][187][188] Fe, [188][189][190] Ga 188 and Ti [191][192][193] have been reported as well (Table 1). Additionally, SAPO and ALPO IZC have been reported and a novel SAPO framework has been discovered (RHO, entry 4) using this synthesis technique.…”

Interzeolite Transformations as a Method for Zeolite Catalyst Synthesis

“…This decline was caused by a partial leaching of silicon from the starting phase. Isomorphically incorporated titanium atoms behave similarly: the Si/Ti ratios are retained during FAU to CHA [21,22] and FAU to AEI [23] transformations, as well as in MWW to BEA [20] transformations. At the same time, the addition of Ti and Sn compounds to amorphous silicon and aluminum sources does not achieve Ti incorporation in such amounts.…”

“…[Ti]AEI d6r Tetraethyl phosphonium [23] Retained Ti atoms isomorphically incorporated into the starting structure. Si/Ti ratio up to 24. pH and dilution, thus decreasing the product yields and Si/Al ratios [11].…”

Revealing scenarios of interzeolite conversion from FAU to AEI through the variation of starting materials

“…19,20 This method has led to the synthesis of a series of small-pore zeolites (such as CHA, AEI and AFX) of high Si/Al ratios and thus enabled superior hydrothermal stability in selective catalytic reduction of NO x with ammonia. 21–23 It was observed that the precrystallized zeolite can give a faster crystallization than do normal silica and aluminum sources to yield the target zeolite, even though the two syntheses were carried out with precursors having an identical composition. 24 These studies suggested that the precrystallized zeolite could offer locally ordered aluminosilicate species that can grow into the target zeolite in a kinetically favorable route.…”