Structural and Catalytic Properties of the Alkali Metal Ion-Exchanged Y-Zeolites by 29Si and 27Al Solid-State NMR and FT-IR Spectroscopy
| Periodical | Key Engineering Materials (Volumes 277 - 279) |
|---|---|
| Main Theme | On the Convergence of Bio-, Information-, Enrivonmental-, Energy-, Space- and Nano-Technolgies |
| Edited by | Kwang Hwa Chung, Yong Hyeon Shin, Sue-Nie Park, Hyun Sook Cho, Soon-Ae Yoo, Byung Joo Min, Hyo-Suk Lim and Kyung Hwa Yoo |
| Pages | 708-719 |
| DOI | 10.4028/www.scientific.net/KEM.277-279.708 |
| Citation | Chang Seop Lee et al., 2005, Key Engineering Materials, 277-279, 708 |
| Online since | January, 2005 |
| Authors | Chang Seop Lee, Hee Jung Lee, Sung Woo Choi, Jahun Kwak, Charles H.F. Peden |
| Keywords | Alkali Metal, Catalytic Activity, Elemental Analysis, FTIR, Non-Thermal Plasma, Solid State NMR, Y-Zeolite |
| Price | US$ 28,- |
A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.
