The Assembly of an All-Inorganic Porous Soft Framework from Metal Oxide Molecular Nanowires

Investigation of the Synthesis of Zeolitic Vanadotungstate and its Use in the Separation of Propylene/Propane at High Temperature and Humidity

Synthetic conditions for the zeolitic octahedral metal oxide based on vanadotungstate are studied. The temperature, time, acidity, W/V ratio, cation species, and concentration affect the resulting materials. The study shows that mixing tungstate and VO²⁺ in an aqueous solution generates cubane units ([W₄O₁₆]^8-) at room temperature. The cubane units assemble with VO²⁺ immediately to form a solid with an amorphous phase and nonporosity, which further crystallizes under a hydrothermal condition to form the crystalline microporous vanadotungstate. The zeolitic vanadotungstates act as effective adsorbents for the separation of propylene/propane. The active materials effectively separate propylene/propane even at high temperatures and high humidities.

Zeolitic octahedral metal oxide-based membranes for pervaporative desalination of concentrated brines

An all-inorganic zeolitic octahedral metal oxide based on cobalt tungstoselenate with porosity and hydrophilicity is successfully used to fabricate a membrane. The as-synthesized membrane and its ion-exchanged membranes exhibit extraordinary permeation flux with high salt rejection by pervaporative desalination for high-salinity brines up to 25 wt%.

Tubular polyoxoanion [(SeMo6O21)2(C2O4)3]10− and its transformations

Tubular [(SeMo₆O₂₁)₂(C₂O₄)₃]¹⁰⁻ polyoxoanion can be assembled from Na₂MoO₄/SeO₂/H₂C₂O₄ system. TBABr precipitates complexes of [Mo₆O₁₉]²⁻ and [β-Mo₈O₂₆Na₂(NO₃)]³⁻ from its aqueous solution. Speciation of [β-Mo₈O₂₆]⁴⁻ and [Mo₆O₁₉]²⁻ has been studied.

Preparation of zeolitic bismuth vanadomolybdate using a ball-shaped giant polyoxometalate for olefin epoxidation

Bismuth vanadomolybdate-based zeolitic octahedral metal oxide was synthesized from {Mo72V30} and used as a heterogeneous catalyst for olefin epoxidation.

Fabrication of Keggin-type Polyoxometalate Membranes at the Gas-Liquid Interface

Keggin-type polyoxometalates are effective catalytic materials for acid-catalyzed reactions and oxidation reactions. In this paper, we describe the fabrication of a porous membrane of Keggin-type polyoxometalates at the gas-liquid interface and the structural characterization of the membrane via aberration-corrected scanning transmission electron microscopy. The membrane is formed by the introduction of n-octylamine vapor into aqueous solution of Keggin-type silicotungstic acid (H₄SiW₁₂O₄₀) and cesium chloride. The membrane obtained has the cubic structure of cesium salts of silicotungstic acid (Cs_xH_4-xSiW₁₂O₄₀), exposing the (110) crystal plane preferentially. The single-unit cell layer of the upper surface of the membrane is densely packed with Keggin anions, while the lower layers are rich in vacancies at both the anion and cation sites. This structure results from the fast formation of the single-unit cell layer at the surface of the solution and slow stacking of Keggin anions under the layer.

Tin oxide-coated transition metal oxide molecular wires for biomass conversion

Herein, acid catalysts were prepared by coating Sn oxide on molecular wires for the production of levulinic acid from cellulose.

Keggin-type polyoxometalate nanosheets: synthesis and characterization via scanning transmission electron microscopy

Polyoxometalate nanosheets were synthesized and their structure was elucidated at the atomic and molecular levels.