New CHA-Type aluminoborosilicates as efficient catalysts for MTO and NH₃-SCR of NO_x reactions

The small-pore CHA-type zeolites have received intensive attentions due to their outstanding performance in both of the methanol-to-olefin (MTO) process and ammonia selective catalytic reduction of nitrogen oxides (NH₃-SCR of NO_x) reactions. However, the costly synthesis of CHA-type aluminosilicate is a great issue for the practical application. In this study, a novel and cheap organic structure-directing agent of N,N,N-trimethylisobutylammonium hydroxide was developed and used to synthesize CHA-type zeolites (name as ECNU-25) with boric acid as the supporting agent. The Si/Al ratio in the synthetic gel could be tailored in a wide range of 50 - ∞. [Al,B]-ECNU-25 zeolite thus synthesized served as an effective catalyst for the MTO reaction. After Cu²⁺-exchange, the Cu-[Al,B]-ECNU-25 was also highly active in the NH₃-SCR of NO_x.