Self-assembled multidoped cryptomelane hollow microspheres with ultrafi ne particles in the size range of 4-6 nm, and with a very high surface area of 380 m 2 g − 1 have been synthesized. The particle size, morphology, and the surface area of these materials are readily controlled via multiple framework substitutions. The X-ray diffraction and transmission electron microscopy (TEM) results indicate that the as-synthesized multidoped OMS-2 materials are pristine and crystalline, with no segregated metal oxide impurities. These results are corroborated by infrared (IR) and Raman spectroscopy data, which show no segregated amorphous and/or crystalline metal impurities. The fi eld-emission scanning electron microscopy (FESEM) studies confi rm the homogeneous morphology consisting of microspheres that are hollow and constructed by the self-assembly of pseudo-fl akes, whereas energy-dispersive X-ray (EDX) analyses imply that all four metal cations are incorporated into the OMS-2 structure. On the other hand, thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) demonstrate that the as-synthesized multidoped OMS-2 hollow microspheres are more thermally unstable than their single-doped and undoped counterparts. However, the in-situ XRD studies show that the cryptomelane phase of the multidoped OMS-2 hollow microspheres is stable up to about 450 ° C in air. The catalytic activity of these microspheres towards the oxidation of diphenylmethanol is excellent compared to that of undoped OMS-2 materials.

Vanadium oxide nanotubes have been formed from the layered vanadium oxide precursor V2O5+ δ[C12H25NH3]. Both the precursor and tubes have been characterized. The black nanotubes have a relatively low thermal stability in oxygen, being oxidized to V2O5 below 200 °C. A new manganese vanadium oxide nanotube, Mn0.1VO2.5+ δ·nH2O, has been synthesized by ion exchange. These manganese tubes have a tetragonal layer with a = 6.157 (3) Å and an interlayer spacing c = 10.52 (3) Å. The nanotubes react with lithium chemically and are also electrochemically active in lithium cells. Two lithium atoms per vanadium can be incorporated chemically from n-butyllithium into both the manganese and the alkylammonium nanotubes. The manganese compound electrochemically intercalates 0.5 lithium per vanadium to a 2 V cutoff, giving a capacity of 140 A h/kg.

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Tungsten was successfully doped at 1 and 2 mol % tungsten into the K-OMS-2 framework. Sodium tungstate and tungsten pentabromide were used in a reflux synthesis preparation. The data collected from the characterization methods collectively affirm the substitution of tungsten into the K-OMS-2 framework. Conductivity measurements showed an increase in the resistivity. Conversion of benzyl alcohol to benzaldehyde had a conversion of 25 and 15% for the sodium tungstate and tungsten pentabromide, respectively, while retaining 100% selectivity. Properties such as the resistivity, thermal stability, and crystallinity of the material were altered depending on the amount and type of starting reactants used.

Vanadium oxide nanotubes (VONT) were formed from vanadium (V) oxide and the dodecylamine templating agent by a sol-gel reaction and subsequent hydrothermal treatment. The nanotubes were characterized by transmission electron microscopy (TEM), electron diffraction, thermogravimetric analysis (TGA), infrared spectroscopy and powder X-ray diffraction (XRD). The nanotubes consist of V0 2 . 4 [CI 2 H28N] 0.27 and range in diameter from 100 nm to150 nm. The study further reveals that the compound maintained the tubular morphology when heated at 4300 C in an inert atmosphere. However, the tubular morphology is destroyed when the compound is heated at about 130°C in oxygen.Organic free manganese intercalated vanadium oxide nanotubes (MnVONT) were synthesized by an ion exchange reaction. The previously mentioned techniques were used to characterize MnVONT. Mno.8 6 V7O16,8 nH20 layers have 2D tetragonal cell with a=6.157(3) A, while interlayer spacing is 10.52 (3) A. VONT, heated VONT and Mno. 86 V 7 0 16 + 5 . nH20 are redoxactive and can insert lithium reversibly. This study reveals that the electrochemical performance of VONT is enhanced by removing the organic template by heating in an inert atmosphere or exchanging with Mn2+ ions.