NSC94-EPA-Z-008-004

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catalysts with pore diameters larger than 0.7 nm Corma et al., (1994(c)) synthesizedTiMCM-41 successfully, this material possessed pore diameters in 2.8 - 3.5 nm and Ticontents up to 2.2 wt %.Figure 2.21 The synthesis mechanism proposed by Lin et al., 1997.It is known that incorporation of transition metal cations in the framework of pure silicapolymorphs of zeolites is not always easy and usually limited to less than 3 wt % (Corma etal., 1994(c)). One of the reason is that these cations have a radius larger than Si 4+ , and theirincorporation in a zeolite framework distorts the latter. Therefore, the zeolite can onlycrystallize within a small metal concentration. Spectroscopic characterization showed Ti 4+ions where isolated in silica domains only for very low Ti contents (< 2 wt%). For highercontents, UV-visible spectroscopy revealed the presence of partially polymerized Ti species,Corma et al. (1994(d)) prepared TiMCM-41 containing 2.2 wt% Ti and concluded that Tiatoms were isolated and tetrahedrally coordinated.Although the thin wall (about 1nm) might be the main cause of the limited stability,MCM-41 is thermally stable under an inert atomsphere below 1273℃ (Rhee et al., 1996).Ryoo et al. (1996) claimed that the structure of MCM-41 was lost completely upon boiling inwater for 2 days due to hydrolysis of silicate. The stability of TiMCM-41 was found to be lowcompared to pure-silicious MCM-41, the substitution of Ti for Si in the silica framework ofMCM-41 greatly reduce the stability of the structure (Koyano et al., 1997).16
In this work, the synthesis of TiMCM-41 materials, and characterization of the catalystsby XRD, FTIR, UV-visible, DTA, TEM, and nitrogen sorption were investigated. Thematerials were tested for CO 2 reacting with H 2 O to form methanol.17
Page 8 and 9: Figure 4.6 25-TiMCM-41 Isothermal P
Page 10 and 11: List of TablesTable 2.1 The compari
Page 12 and 13: Chapter2. Literature Review2.1 Cata
Page 14 and 15: In order to know exactly the influe
Page 16 and 17: exhibit different structures and re
Page 18: The different properties in H 2 O a
Page 22 and 23: Figure 2.16 MCM-41 structure with h
Page 24 and 25: Figure 2.18 The synthesis mechanism
Page 28 and 29: Chapter3. Experimental3.1 Chemicals
Page 30 and 31: 3.4 Characterization(1) X-ray Diffr
Page 32 and 33: Na2O‧ 2SiO2‧nH2O +H2OmixingTi s
Page 34 and 35: Chapter4. Results and Discussion4.1
Page 36 and 37: different opinion about the equidis
Page 38 and 39: Figure 4.3 XRD patterns of 50-TiMCM
Page 40 and 41: 350Volume Adsorbed cm 3 /g STP30025
Page 42 and 43: Table 4.2 Wall thickness of TiMCM-4
Page 44 and 45: 2.01.6MCM-4125-TiMCM-4175-TiMCM-41T
Page 46 and 47: 4.2 Photoreduction under visible li
Page 48 and 49: Intensity (arb. units)CB0 10 20 30
Page 50 and 51: (C) 1.0 wt% NiO/InVO 4Figure 4.17 T
Page 52 and 53: Table 4.3 The nominal and actual lo
Page 54 and 55: 4.2.2 Effect of reduction-oxidation
Page 56 and 57: Intensity (arb. units)CB0 10 20 30
Page 58 and 59: (C) 1.0 wt% NiO/InVO 4 R500-O200Fig
Page 60 and 61: 2.4Methanol yield (μmol g -1 h -1
Page 62 and 63: Chapter6. ReferencesAlfredsson, V.;
Page 64 and 65: Mesoporous Molecular-Sieves Snthesi
Page 66 and 67: 劃暨子計劃一主持人
Page 68: 子計畫 ); 系統放大設

NSC94-EPA-Z-008-004

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