Novel Technique to Synthesize AFX-Type Zeolite Using a Bulky and Rigid Diquaternary Ammonium Cation

Formation and Reactions of NH4NO3 during Transient and Steady-State NH3-SCR of NOx over H-AFX Zeolites: Spectroscopic and Theoretical Studies

“…33 Recently, Kubota and co-workers developed a highly durable AFX zeolite using a bulky, non-flexible OSDA (TEBOP 2+ ). 28 In this study, we employed this H-type AFX (H-AFX) while performing operando infrared (IR) spectroscopy, kinetics and density functional theory (DFT) analyses to elucidate the role of NO2 in NH3-SCR under both steady-state and transient conditions. Herein, we propose mechanisms for the transformation of NO2 to N2 or N2O via NH4NO3 over H-AFX on the basis of the experimental evidence.…”

Zeolite Synthesis under Nonconventional Conditions: Reagents, Reactors, andModi Operandi

“…CHA, RHO, AEI and RTH) can be synthesized from a FAU precursor. [110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127][128][129] Thermodynamic studies have demonstrated that idealized frameworks with higher framework density are slightly more stable than structures with low framework density (with respect to α-Quartz). 130 Nevertheless, the use of an OSDA changes the stabilization of the materials resulting from synthesis significantly.…”

Ultrafast synthesis of AFX-Type zeolite with enhanced activity in the selective catalytic reduction of NOx and hydrothermal stability

“…The 20 wt% solution of TEBOP (for molecular structure see Fig. S3 †) was prepared by a slightly modied recipe reported elsewhere 43 . In a typical SSZ-16 synthesis, a reactant with a molar composition of 1.0SiO 2 -0.092Al 2 O 3 -0.1NaOH-0.1TEBOP-20.0H 2 O involving FAU type zeolite (HSZ-350HUA, Tosoh, SiO 2 /Al 2 O 3 ¼ 10, H + type) as both Si and Al sources was prepared by stirring at room temperature for 2 h under 400 rpm.…”

“…So far, several exible OSDAs have been employed for preparing SSZ-16, [43][44][45][46][47][48][49][50] but recently, a bulky OSDA with a rigid structure named TEBOP, oen involved in the synthesis of MSEtype zeolites, was introduced for the synthesis of SSZ-16. 43,44 However, it required at least 24 h for preparing the SSZ-16 using TEBOP in an autoclave and achieving it at a faster pace remained challenging because the degree of synthesis freedom offered by such small pore zeolites are quite narrow. 43,44 Extending the ultrafast synthesis approach, we were able to synthesize SSZ-16 (AFX-type) zeolite in 2 hours using sealed tubular reactor which would otherwise require several days.…”

“…43,44 However, it required at least 24 h for preparing the SSZ-16 using TEBOP in an autoclave and achieving it at a faster pace remained challenging because the degree of synthesis freedom offered by such small pore zeolites are quite narrow. 43,44 Extending the ultrafast synthesis approach, we were able to synthesize SSZ-16 (AFX-type) zeolite in 2 hours using sealed tubular reactor which would otherwise require several days. [45][46][47][48][49][50][51] The SSZ-16 from TEBOP bettered their DABCO counterpart with physio-chemical traits that are promising for enhanced SCR of NOx and in particular they were bestowed with excellent hydrothermal stability.…”