Impact of the Zn source on the RSN-type zeolite formation

Abstract

RSN-type material has been prepared exclusively from Zn containing systems under the studied reaction conditions.

Influence of Framework n(Si)/n(Al) Ratio on the Nature of Cu Species in Cu‐ZSM‐5 for NH3‐SCR‐DeNOx

“…in zeolite framework in terms of occupation of specific crystallographic position (T sites), a certain region of the crystal as well as their quantity, i. e., n(Si)/n(T) ratio, is determined by the nature of the T atom itself, the source chemicals of the each T atom, the chemical composition of the reaction mixture (e. g., initial n(Si)/ n(T) ratio, pH), the type of mineralizer as well as the reaction conditions (e. g., temperature, agitation, supersaturation, etc.). [16][17][18][19] Herein, the variations in the framework n(Si)/n(Al) ratio were achieved via changes in the zeolite preparation temperature. The Cu-containing zeolites were characterized in terms of their structure and morphology (XRD, SEM, TEM, ICP-OES, NMR), texture (N 2 sorption), acidity (FT-IR studies of pyridine (Py) sorption), the nature of the copper species (DR UV-Vis, TEM and EPR) and were investigated as the catalysts for the NH 3 -SCR-DeNO x .…”

“…in zeolite framework in terms of occupation of specific crystallographic position (T sites), a certain region of the crystal as well as their quantity, i. e., n (Si)/ n (T) ratio, is determined by the nature of the T atom itself, the source chemicals of the each T atom, the chemical composition of the reaction mixture (e. g., initial n (Si)/ n (T) ratio, pH), the type of mineralizer as well as the reaction conditions (e. g., temperature, agitation, supersaturation, etc.) [16–19] . Herein, the variations in the framework n (Si)/ n (Al) ratio were achieved via changes in the zeolite preparation temperature.…”

Defect Sites in Zeolites: Origin and Healing

“…[10] Indeed, zeolite synthesis conditions directly affect the properties of the final product at all levels, from the nature of the T atom incorporated in the framework, the morphology, and the size of formed crystals, but also the level of crystallinity, the size of the coherent crystalline domains and the framework defects. [15,16] As an illustration, recently, Tanigawa et al have shown that the variation in the Si/Al ratio in the synthesis mixture as well as changing the Si and/or Al sources yields CHA-type materials of different sizes. [17] Shinno et al reported that the initial content of Ge controls the phase composition of the end product in the preparation of chiral STW-type material.…”

Mechanochemically Induced OSDA-Free Interzeolite Conversion

“…8−11 Typical zeolite synthesis is a rather slow "geo-inspired" process involving hydrothermal treatment of (Al)Si-containing (amorphous) precursors in highly alkaline solutions at temperatures ≤250 °C for several hours and up to several weeks. 15,16 As these processes come with great energy demand and generate a significant amount of corrosive waste, seeking more efficient, greener, and controllable zeolite production procedures represents a constant aspiration in line with the UN and EU recommendations.…”

“…17 Thus, new preparation avenues are necessary to synthesize novel, versatile zeolite materials and expand their application potential. 16,22,23 Mechanochemical reactions induced by mechanical energy (compression, shear, or friction) are developing into a powerful green synthetic tool with unprecedented control over the reaction. mechanochemistry may provide alternative reaction pathways toward products unavailable by other synthesis approaches.…”