Synthesis of high silica mordenite nanocrystals using o-phenylenediamine template

High silica mordenite samples (Si/Al molar ratios 38 and 60) were synthesized hydrothermally at 433 K with the template route method using o-phenylenediamine and characterized with several techniques including XRD, FT-IR, TG/DTA, pyridine-FTIR and N2 adsorption. The effects of Na2O/SiO2 ratio, Si/Al ratio, temperature, crystallization time and various templates on mordenite crystallization as well as crystallite size that was smaller than 50 nm, irrespective of varying the parameters were thoroughly investigated. The effect of alkali cations such as Na+ and K+ on mordenite crystallization and on thermal stability of the produced mordenite was also investigated. Pyridine adsorption suggests an increase in Lewis acid sites particularly following hydrothermal treatment at 120 °C where at 160 °C both Lewis and Brönsted acid sites in addition to oxidation products, which are indicative of the existence of dual acid-base sites, were exposed. Surface texturing of the produced samples were correlated with their thermal analyses data.