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The cooperative use of the Cu‐tetraethylenepentamine complex and N,N,N‐trimethyl‐1‐adamantammonium as organic structure‐directing agents (OSDAs) enabled the rationalized “one‐pot” preparation of Cu‐containing SSZ‐13 zeolites. A detailed study of different synthetic variables permitted the control of the Si/Al and Cu/(Si+Al) ratios in the final solids. Cu‐SSZ‐13 molecular sieves synthesized in alkaline media demonstrate excellent catalytic activities and good hydrothermal stabilities for the selective catalytic reduction of NOx. Finally, the effect of synthesis media on the catalytic active sites is also demonstrated and a remarkable activity loss for samples synthesized in fluoride media is observed.

ElsevierMartinez Franco, R.; Moliner Marin, M.; Concepción Heydorn, P.; Thogersen, JR.; Corma Canós, A. (2014). Synthesis, characterization and reactivity of high hydrothermally stable Cu-SAPO-34 materials prepared by one-pot processes. Journal of AbstractA Cu-SAPO-34 material with very high activity for selective catalytic reduction (SCR) of NOx and hydrothermal stability has been synthesized following a sequential rationalized design. By using specific combinations of organic structure directing agents (OSDAs) and gel compositions in a "one-pot" method, it was possible to control Cu occupancy, framework Si distribution, and to maximize the yield of solids. The amount of Cu 2+ is maximized and remains stable even after steaming at 750ºC for 13 hours. Highlights-A rationalized methodology has allowed the one-pot synthesis of Cu-SAPO-34zeotypes.-An optimized Cu-SAPO-34 shows high activity and hydrothermal stability for SCR-NOx.-Cu 2+ species remain in the optimized Cu-SAPO-34 even after severe ageing. KeywordsOne-pot synthesis, silicoaluminophosphate, SAPO-34, selective catalytic reduction (SCR), nitrogen oxides (NOx) 4 1.-IntroductionThe design of an attractive heterogeneous catalyst for a relevant chemical process,involves the synthesis of materials with high activity, selectivity, and stability.Moreover, if the catalyst is mean to be used industrially, the synthesis procedure should be economically competitive. In many cases, the combination of innovative work together with accumulated knowledge allows to achieve new synthesis that not only improves the physico-chemical properties of the catalysts but can meet the economical targets.In the last years, the synthesis of small pore zeolites with large cavities containing extra-framework cationic metals, such as Cu 2+, has received much attention thanks to their excellent activity and stability for the selective catalytic reduction (SCR) of NOx.[1]Traditionally, copper species are introduced in small pore zeolites by post-synthesis cationic exchange-impregnation methods.[ 1 ,2] However, the distribution of Cu within the zeolitic crystals following these procedures can be limited by diffusion of the Cu due to the presence of small pores (openings  3.5 Å), being the metal preferentially located close to the external surface. [3] To avoid this, different "one-pot" synthesis methods introducing organo-copper complexes in the synthesis gel have been recently described.[4] These direct procedures permit better metal dispersion within zeolitic crystals, and also allow reducing the overall synthesis steps required to achieve the final Cu-zeolite catalyst.[5] Diverse Cu-complexes and synthesis conditions have been reported in the last years to direct the "one-pot" preparation of different small pore chabazite (CHA) polymorphs, as Cu-SSZ-13, [4a,6] and Cu-SAPO-34. [4b,7] In a previous report, we have described the direct preparation of Cu-SAPO-34 using a combination of diethylamine (DEA) and Cu-tetraethylenepentamine (Cu-TEPA) as organic structure directing agents (...

Cage-based small-pore catalysts for NH3-SCR prepared by combining bulky organic structure directing agents with modified zeolites as reagents.

The preparation of the iron‐containing SSZ‐39 zeolite is described for the first time through two different synthesis methods: post‐synthetic cation exchange and one‐pot synthesis. The nature and stability of the iron species within the different Fe‐SSZ‐39 materials have been studied through different characterization techniques, and their catalytic activity has been evaluated for the selective catalytic reduction (SCR) of NOx with ammonia. The directly synthetized Fe‐SSZ‐39 performs better for the SCR of NOx with ammonia than other related Fe‐zeolites, particularly at elevated reaction temperatures (above 450 °C), and presents improved hydrothermal stability when aged under severe conditions.