Intercalation of polyoxycation species into conducting layered host lattices of molybdenum trioxide and tantalum disulfide

Abstract

Strukul, G.; (7) Mazzocchia. C.: Temuesti. E.; Gronchi, P.; Giuffre, L.; Zanderighi, L.Zanderighi, L. J. Coral. 1985, 96, 106. J . i.aia/. 1988, iii, 345. * (8) Guglielminotti, E. J. Caral. 1989, 120, 287. (9) Yashitake. H.; Iwasawa, Y., to be published. (IO) Yashitake, H.; Iwasawa, Y., to be published. (11) Sayers, D. A.; Stern, E. A,; Lytle, F. W. Phys. Rev. Lett. 1971, 35, (12) Oyanagi, H.; Matsushita, T.; Ito, M.; Kuroda, H. KEK Rep. 1984, (13) Kasugi, N.; Kuroda, H. Program EXAFS2; Research Center for -204. 83. Nomura, M. KEK Rep. 1985, 85. Polyoxycations [A104A112(OH)24 ( H Z O )~~]~' and [B&(OH)lz]6+were introduced into highly crystalline MOO3 (space group Pnma) and 2H-TaSz (P6,lmmc) by ion exchanging the sodium forms of hydrated layered compounds. Interlayer spacing in MOO, increases from 6.97 to 18.1-18.9 A, more than would be expected from the sum of the spacing in the parent compound and the diameter of the All, polyoxycation. We suggest that the MOO, layers in the intercalated material are shifted with respect to one another, so that the terminal oxygen atoms of the MOO6 octahedra of adjacent layers point toward each other. The heat-treated material has a higher degree of stacking order, and it is clear that the Al13 unit survives the heat treatment. z7Al MAS and 'H2N CP/MAS NMR spectra reveal that Merent environments for interstitial aluminum are simultaneously present in the sample. The [B~(OH)lz]6+ cation was introduced into a layered host lattice for the first time. The interlayer distance of the product is 13.8 A, in agreement with the largest oxygen-oxygen distance in the cation.

Microstructural Characterization of Highly HDS-Active Co6S8-Pillared Molybdenum Sulfides

“…Several groups, particularly those of Chianelli, Frindt, Nazar, − Fuentes, Curtis, and Wypych have exfoliated Li x MoS 2 in H 2 O to form a restacked MoS 2 , usually with surface areas of 10 m 2 /g but occasionally as high as 50 m 2 /g and much higher than the 5−6 m 2 /g MoS 2 obtainable from commercial vendors. Several reports, − ,, particularly those of Nazar, have appeared recently on the subject of pillared layered chalcogenides as well. Not until the preparation of this paper had intercalated chalcogenides been tested for hydrodesulfurization activity, however.…”

Transformations of the aluminum (Al13) polyoxycation intercalated in the layered lattice of molybdenum trioxide

“…CP/MAS spectra15 were recorded with a single contact, a contact time of 500 ms, a 'H 90°p ulse of 3.4 ms, a recycle delay of 5 where yA! and yH denote the gyromagnetic ratios of 27A1 and 'H and B is the radio-frequency field strength.…”

“…However, 6-coordinated Al in solid Al)3 can be observed by MAS NMR. The intensity ratio of the lines from 6-and 4-coordinated Al is often different from the expected value of 12, which may be due to the radio-frequency pulse-width effect or the relative populations of the sites.2 4 The resonance at 0 ppm is a composite containing a peak from the monomeric A1(H20)63+ cation and a line from at least one other 6-coordinated species.2 5 Elemental analysis and measurements of the cation-exchange capacity have shown that the effective charge of the guest species in clays is lower than the nominal value of 7+, and it has been proposed that the actual charge is 4+i4,9,10…”

“…Intercalation is easy and, unlike in clays, the XRD pattern of the product shows a number of well-resolved reflections.511 Also, irrespective of whether aluminum chlorohydrate or A1C13 hydrolyzed with NaOH is used for intercalation, the same increase in the interlayer spacing is observed, from 11.5 A in the starting molybdenum bronze to 18.1 A. 5 The XRD pattern indicates that the Mo03 layers in the intercalate are shifted with respect to one another, so that the terminal oxygen atoms of the M0O6 octahedra of adjacent layers point toward each other (Figure 1), while in the starting material they point toward the space between the Mo06 octahedra of the neighboring layers.5 In view of the high crystallinity of the samples, the orientation of the Al 13 species between the layers (see Figure 1) could be determined using onedimensional Fourier analysis.11 Crystallinity of the intercalate decreases upon heat treatment, with the formation of aluminum molybdate starting at ca. 400 °C (XRD), and we have reported preliminary NMR work for as-synthesized and heat-treated samples.5 Here we discuss the results of conventional27Al MAS NMR, 'H-27A1 cross-polarization (CP) with MAS, and27Al MAS quadrupole nutation experiments, carried out with Al polyoxycations introduced into a layered host lattice of M0O3 from different solutions and for partial and complete intercalation.…”

Materials and Models: Faces of Intercalation Chemistry

“…Similarly, the Cllayer anions can be replaced by tetrahedral anionic groups, e.g., [Fe(CO)4f- [242]. Guest compounds used for this purpose have been, e.g., metal cluster ions [246], metal complex ions with large ligands [247], polyoxometallates [248,249], the tubular alumino silicate imogolite ( Figure 22) [250]. A different approach is the insertion of isometric guest species with large diameter into layered host lattices, which are immobilized by secondary reactions.…”