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

BACKGROUND A series of Cu-SAPO-34 samples were prepared with different copper sources and addition of tetraethylenepentamine (TEPA) by a one-pot method, which were applied for selective catalytic reduction of NO x with ammonia (NH 3 -SCR). RESULTS Various measurements were carried out to investigate the effect of TEPA addition and copper sources used on sample properties. The results indicated that Cu-SAPO-34 obtained with the addition of TEPA using copper citrate (Cu-SAPO-34-TC) displayed over 90% NO x conversion at 150–500 °C and excellent H 2 O and SO 2 resistance in NH 3 -SCR. This is because the addition of TEPA can control the formation of isolated Cu 2+ species located at the junction of D6R in CHA cage, Site (I), which is regarded as a more easily approachable site to adsorbates (NH 3 and NO) than others, thus leading to the excellent NH 3 -SCR performance. Further study demonstrated that the Cu-SAPO-34-TC catalyst shows much wider temperature window and more hydrothermal stability due to a greater amount of surface isolated Cu 2+ , fewer Si islands and more Al(IV) species. CONCLUSIONS The excellent activity of the Cu-SAPO-34-TC catalyst can be attributed to the addition of TEPA, which is beneficial for controlling the isolated Cu 2+ at Site (I) as well as inhibiting the aggregation of CuO species. Various characterizations also confirm that more surface Cu 2+ can be produced using copper citrate as copper source. © 2022 Society of Chemical Industry (SCI).