The Study on Location and Adsorbate Interaction for Vanadium Species in VO2+-SAPO-5 by Electron Spin Resonance and Electron Spin Echo Modulation Spectroscopies
1
조회
0
다운로드
0
인용
0
참고문헌
초록
영어논문
Abstract
Vanadium-incorporated aluminophosphate molecular sieve VO2+-SAPO-5 was studied by electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies to determine the vanadium structure and interaction with various adsorbate molecules. It was found that the main species at low concentration of vanadium is a monomeric vanadium units in square pyramidal or distorted octahedral coordination, both in oxidation state (IV) for the calcined hydrated material and in oxidation state (V) for the calcined material. After calcinations in O2 and exposure to moisture, only species A is observed with reduced intensities. It is suggested as a VO(H2O)32+ complex coordinated to two framework oxygen bonded aluminum. When calcined, hydrated VO2+-SAPO-5 is dehydrated at elevated temperature, a species loses its water ligands and transforms to VO2+ ions coordinated to two framework oxygens (species B). Species B reduces its intensity, significantly after treatment with O2 at 600 oC for 5 h, thus suggesting oxidation of V4+ to V5+. When dehydrated VO2+-SAPO-5 contacts with D2O at room temperature, the EPR signal of species A is observed. Thus species assumed as a VO2+(Of)2(D2O)3, by considering two framework oxygens. Adsorption of deuterated ethanol, propanol on dehydrated VO2+-SAPO-5 result in another new vanadium species E and F, respectively, which are identified as a VO2+-(CH3CH2OD)3, VO2+-(CH3CH2CH2OD)2 complex. When deuterated benzene is adsorbed on dehydrated VO2+-SAPO-5, another new vanadium species G, identified as a VO2+-(C6D6) is observed. Possible coordination geometries of these various complexes are discussed.
참고문헌 (25)
- A. M. Prakash, "J. Phys. Chem. B 103. 2214 (1999)", J. Phys. Chem., 103 (1999)
- T. Blasco, "J. Catal. 152, 1, (1995)", J. Catal., 152 (1995)
- M. S. Riutto, "J. Mol. Catal. 81, 77, (1993)", J. Mol. Catal., 81 (1993)
- S. H. Jhung, "Appl. Catal. 62, 61, (1990)", Appl. Catal., 62 (1990)
- M. J. Haanpen, "Appl. Catal. A 152, (1997)", Appl. Catal., 152 (1997)
- C. Montes, "J. Phys. Chem. 94, 6431 (1990)", J. Phys. Chem., 94 (1990)
- B. M. Weckhuysen, "Zeolites, 15, 482, (1995)", Zeolites, 15 (1995)
- G. Centi, "J. Phys. Chem. 96, 2617, (1992)", J. Phys. Chem., 96 (1992)
- PuyamS. Singh, "J. Mol. Catal. A, Chemical 104, 103, (1995)", J. Mol. Catal. A, Chemical, 104 (1995)
- E.M. Flanigen, "Europe Patent 158,976, (1985)", Europe Patent, 158 (1985)
- R. V. Ballmoos, "Collection of Simulated XRD Powder Patterns for Zeolites" (1984), Butterworth Scientific; Surrey
- A. M. Prakash, "J. Phys. Chem. B 104, 6860 (2000)", J. Phys. Chem., 104 (2000)
- K. A. Viswanath, "J. Chem. Phys. 67, 3744 (1977)", J. Chem. Phys., 67(3744) (1977)
- B.N. Mirsaand, "Chem. Phys. Lett. 46, 536 (1977)", Chem. Phys. Lett., 46 (1977)
- M.S. Girutto, "J. Mol. Catal. 81, 77 (1993)", J. Mol. Catal., 81(77) (1993)
- X. Chen, "J. Am. Chem. Soc. 113, 2816 (1991)", J. Am. Chem. Soc., 113 (1991)
- J.-S. Yu, "Zeolite Science 1994 : Recent Progress and Discussion B. Dolmon, J. T. Yatos, H. G. Karge and J. Weitkamp Eds. Studies in Surface Science and Catalysis, vol. 98", pp.77~ (1994), Elsevier : Amsterdam,
- Jr. T. Mu Ñ, "J. Phys. Chem. B, 102, 137 (1998)", J. Phys. Chem., 102 (1998)
- Di Gregorieo S, "J. Chem. Phys. 76, 2931 (1982)", J. Chem. Phys., 76 (1982)
- G. Back, "J. Kor. Mag. Res. Soc. 20(1), 1 (2005)", J. Kor. Mag. Res. Soc., 20(1) (2005)
- M.S. Rigutto, "J. Mol. Catal., 81 (1993)", J. Mol. Catal., 81 (1993)
- M. Zamadics, "J. Phys. Chem. 96, 8989 (1992)", J. Phys. Chem., 96 (1992)
- J.-S. Yu, "J. Phys. Chem, 97, 10433 (1993)", J. Phys. Chem., 97 (1993)
- H.J. Gerritsen, "Phys. Rev. 119, 1010 (1960)", Phys. Rev., 119 (1960)
- L. Kevan, "Time Domain Electron Spin Resonance; L. Kevan, and R. N. Schwartz, Eds." (1978), Wiley : New York