Synthesis and characterization of Ti-STF zeolite using 1,2,3-triethyl-4-methylimidazolium as structure-directing agent

A new composition of STF zeolite, Ti-STF, was synthesized via the fluoride route using 1,2,3-triethyl-4-methylimidazolium (123TE4MI) as a structure-directing agent (SDA). The Si/Ti ratios used in the synthesis of the Ti-STF materials were 50 and 25, and the synthesis of pure silica STF, as a blank, was also carried out. The obtained materials were studied and characterized by different techniques such as X-ray diffraction, 13C and 27Si solid-state NMR, thermogravimetric analysis, among others. Additionally, the Ti incorporated into the STF zeolite framework was studied by diffuse reflectance ultraviolet–visible (UV–vis) spectroscopy. This characterization showed that Ti species are mostly tetrahedrally coordinated in the STF zeolite framework; however, a minority of Ti is octahedrally coordinated, i.e., extra-framework.