Ongoing global climate disruption stimulates research into methods that reduce, recycle, and/or store greenhouse gases. Titanium-substituted zeolites such as titanosilicate-1 (TS-1) and titanosilicate beta (Ti-BEA) are excellent oxidative photocatalysts and also exhibit photo-reduction chemistry. In this study, we focus on Ti-BEA because of its 12MR ring size, which facilitates the exchange of reactants and products as compared to the MFI framework (10MR). Our goal is to study the photocatalytic reduction of CO2 and H2O to methanol using Ti-BEA powders.1Pure silica BEA and Ti-BEA were synthesized according to modified literature methods2,3. Both doped and undoped forms of BEA were prepared and the growth conditions studied to compare and understand the growth rate and conditions of Ti-BEA. Progress of BEA crystallization from amorphous material to highly crystalline beta zeolite framework was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and magic angle spinning nuclear magnetic resonance (MAS-NMR). Hydrothermal synthesis of Ti-BEA was modified to by the novel use of titanium(IV) tetrafluoride as the titanium source, which reduces the amount of hydrofluoric acid3 insynthesis. Fluoride is a needed mineralizing agent to produce a nearly defect-free (few Q3 sites) zeolite. XRD patterns and SEM images obtained before and after calcination show that pure monophasic Ti-BEA was obtained. UV-Vis and 29Si MAS-NMR spectroscopy were performed on calcined material and compared to published spectra3. Titanium content in Ti-BEA was determined by energy dispersive X-ray spectroscopy (EDS) and UV-Vis spectroscopy. Photocatalytic reduction of CO2 and H2O to methanol and quantity of methanol produced determined by gas chromatography.References Ikeue, K., Yamashita, H., Anpo*, M. J. Phys. Chem. B 2001, 105, 8350-8355.Camblor*, M. A., Corma, A., Valencia, S. Chem. Commun. (1996): 2365-2366.Blasco, T., Camblor*, M. A., Corma, A. J. Phys. Chem. 102.1 (1998): 75-88.

Synthesis and characterization of zeolite beta (BEA) and titanosilicate beta (Ti-BEA) using titanium(IV) tetrafluoride

248th National Meeting (2014)

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