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

Abstract

SSZ-16 (AFX-type) zeolite prepared in 2 h, so far the fastest, shows enhanced hydrothermal-stability and activity in selective-catalytic-reduction of NOx.

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

“…28,29 Cu-modified AFX zeolites have recently attracted much attention as effective catalysts for the NH3-SCR reactions. 4,[30][31][32] The AFX zeolites referred to as SSZ-16 have typically been synthesized using a flexible organic structure-directing agent (OSDA). 33 Recently, Kubota and co-workers developed a highly durable AFX zeolite using a bulky, non-flexible OSDA (TEBOP 2+ ).…”

“…AFX zeolite is an eight-membered-ring (that is, small-pore) material having both aft cages (0.55 × 1.35 nm) and smaller gme cages (0.33 × 0.74 nm). , Cu-modified AFX zeolites have recently attracted much attention as effective catalysts for NH 3 -SCR reactions. ,− The AFX zeolites referred to as SSZ-16 have typically been synthesized using a flexible organic structure-directing agent (OSDA) . Recently, Kubota and co-workers developed a highly durable AFX zeolite using a bulky, nonflexible OSDA (TEBOP 2+ ) .…”

Advances in Catalytic Applications of Zeolite‐Supported Metal Catalysts

“…In addition to the CHA zeolite, many other types of zeolites, such as 8‐MR zeolites LTA, [ 16b,202 ] ERI, [ 203 ] AFX, [ 204 ] AEI, [ 205 ] KFI, [ 206 ] UFI, [ 202a ] RHO, [ 207 ] and RTH, [ 208 ] 10‐MR zeolites MFI, [ 209 ] SFW, [ 210 ] and FER, [ 211 ] and 12‐MRs zeolite MOR, [ 212 ] MSE, [ 213 ] and *BEA, [ 214 ] were also used as effective supports to anchor the Cu species for the NH 3 ‐SCR reaction. The hydrothermal stability and SO 2 resistance of Cu‐containing zeolites were key factors to meet the practical requirements in NH 3 ‐SCR reactions and numerous studies have been focused on these topics in the recent decade.…”

Influence of hydrothermal time on the formation of SAPO-56 structure and its catalytic activity of removal NOx by NH3-SCR with Cu/SAPO-56

“…Hiện nay, các loại xúc tác sử dụng chất mang có khung cấu trúc AFX (Cu/SSZ-16, Cu/SAPO-56) [6] và vật liệu khung chabazit (CHA) như Cu/SAPO-34 hay Cu/SSZ-13 [2] đang được quan tâm nghiên cứu ứng dụng cho quá trình NH3-SCR. Đặc biệt, SSZ-16 và Cu/SSZ-16 gần đây nhận được nhiều sự chú ý hơn cả do chúng có độ bền thủy nhiệt tốt, khoảng nhiệt độ hoạt động rộng (200 -600 °C) và độ chuyển hóa NOx gần như đạt 100% [7]. SAPO-56 là vật liệu vi mao quản, có cấu trúc dạng AFX giống với vật liệu SSZ-16, là liên kết của ba chuỗi lồng (d4r, gme, aft) có kết cấu khung tinh thể khác nhau tạo thành các ô mao quản với kích thước khoảng 3,4 -3,6 Å [8].…”