A reconstruction strategy for the synthesis of Cu-SAPO-34 with excellent NH3-SCR catalytic performance and hydrothermal stability

One‐pot facile synthesis of Cu‐SAPO‐34 via addition of tetraethylenepentamine and its enhanced catalytic activity in selective catalytic reduction of NOx with NH3

“…In previous work, it was reported that the location of isolated Cu 2+ in the Cu-SAPO-34 structure was very important for its NH 3 -SCR performance. 7,20 EPR spectroscopy is an efficient method for discriminating the cooperative environment of isolated Cu 2+ in Cu-SAPO-34, because only isolated Cu 2+ species can create EPR signals among these Cu species. As displayed in Fig.…”

“…Cu‐CHA zeolites, such as Cu‐SSZ‐13 and Cu‐SAPO‐34, have attracted a lot of interest recently because of their remarkable NH 3 ‐SCR activity over a wide temperature range and high hydrothermal stability 7 . The extremely effective NH 3 ‐SCR catalysts have tightly connected redox‐acid sites, high copper dispersion and appropriate exposure, which might be satisfied by copper zeolites prepared by the ion‐exchange method 8 .…”

“…Cu-CHA zeolites, such as Cu-SSZ-13 and Cu-SAPO-34, have attracted a lot of interest recently because of their remarkable NH 3 -SCR activity over a wide temperature range and high hydrothermal stability. 7 The extremely effective NH 3 -SCR catalysts have tightly connected redox-acid sites, high copper dispersion and appropriate exposure, which might be satisfied by copper zeolites prepared by the ion-exchange method. 8 However, Cu-SAPO-34 synthesized using this method normally undergoes irreversible hydrolysis during the ion-exchange process, leading to low specific surface area, small micropore volume and poor crystallinity.…”

Influence of Copper Locations on Catalytic Properties and Activities of Cu/SAPO-34 in C3H6-SCR

“…Two broad NH 3 desorption peaks could be observed in the curve of H-SAPO-34. The peak below 300 °C can be assigned to weakly adsorbed NH 3 on surface hydroxyl groups, 27,31 while the desorption peak at higher temperature (400−550 °C) is related to the structural Brønsted acid sites, corresponding to the Si(nOAl, n = 1−4) groups in SAPO-34, the acidic strength of which follows the sequence Si(1OAl) > Si(2OAl) > Si(3OAl) > Si(4OAl). 43 However, the desorption peak corresponding to the structural Brønsted acid sites is weakened, owing to the proton (Si−OH−Al) being substituted by Cu 2+ species.…”

“…Compared to mesoporous or macroporous Cu-based zeolite catalysts, Cu-exchanged silicoaluminophosphate-34 (SAPO-34) catalysts with a microporous chabazite (CHA, 0.38 nm pore size) structure exhibit superior hydrothermal stability. − Accordingly, since 2009 Cu/SAPO-34 catalysts have been extensively employed and researched in NH 3 -SCR reactions, focusing on the synthesis method, − effect of crystallinity, , silicon content and acid sites, − effect of Cu loadings, , resistance to H 2 O or SO 2, − and copper migration during hydrothermal treatment. , The Cu/SAPO-34 catalysts show prominent NH 3 -SCR activity, wide operation window, superior hydrothermal stability, and high N 2 selectivity . However, in the field of HC-SCR, the Cu/SAPO-34 catalysts did not attract much attention.…”