Weibin Liang

Microwave-assisted solvothermal synthesis of zirconium oxide based metal-organic frameworks.

Zirconium oxide based Metal-Organic Frameworks were synthesised using a rapid and efficient microwave-assisted solvothermal method that produced purer phases and higher quality crystalline products in significantly (>95%) less time than the conventional heating method. A new amino-functionalised analogue has been synthesised exclusively using this microwave-assisted methodology.

Microwave-assisted solvothermal synthesis and optical properties of tagged MIL-140A metal-organic frameworks.

A series of tagged MIL-140A-R frameworks have been synthesized using a microwave-assisted solvothermal method. Compared with their UiO-66-R polymorphs, the absorption energies in the MIL-140A-R series (R = NH2, NO2, Br, Cl, and F) are extended toward the visible region because of the spatial arrangement of the linkers.

Biogenic synthesis of photocatalytically active Ag/TiO2 and Au/TiO2 composites

In this work, spherical Ag and Au nanoparticles, primarily below 10 nm in diameter, were synthesised by contacting biological extracts from the vascular plant Citrus limon with aqueous Au3+ and Ag+ solutions at ambient temperature. The chemical constituents of the plant extract acted as reducing, capping and stabilising agents, and nanoparticle size and shape could be tuned by adjusting the pH of the extract suspension. Au nanoparticles synthesised at pH = 7 and Ag nanoparticles synthesised at pH = 11 were monodisperse and well-defined. Thin films of these Au and Ag nanoparticles were coated onto TiO2 by colloidal deposition and the resulting composites were tested as catalysts for the degradation of an organic dye. 1 wt% Au/TiO2 and Ag/TiO2 composites were at least as active as M/TiO2 composites prepared by reduction with NaBH4.

Tuning pore size in a zirconium–tricarboxylate metal–organic framework

The water-stable zirconium–tricarboxylate series of frameworks, [Zr6O4(OH)4(X)6(btc)2]·nH2O, where X = formate (F), acetate (A), or propionate (P), exhibit tunable porosity by virtue of systematic modulation of the chain length of the monocarboxylate ligand X. This modification not only impacts the pore size of the framework, but provides an important avenue for the construction of mixed-linker MOFs.

Photoresponsive spiropyran-functionalised MOF-808: postsynthetic incorporation and light dependent gas adsorption properties

The first example of a spiropyran-incorporated metal–organic framework was synthesised via a two-step post-synthesis modification of the Zr-oxo nodes in MOF-808. The incorporated spiropyran could not otherwise be obtained via the analogous one-step de novo synthesis. The resulting MOF-808-SP showed a photoresponsive surface area, pore volume and CO2 uptake, relevant for light-dependent gas separations processes.

Surface functionalized UiO-66/Pebax-based ultrathin composite hollow fiber gas separation membranes

Pebax-based composite hollow fibre membranes are promising candidates for industrial gas separation, but their application is limited by the inherent separation performance of the polymeric materials and the poor operational stability especially under elevated pressures. The incorporation of metal–organic frameworks (MOFs) has been extensively investigated as a potential solution to these problems. However, the major challenges are to control the microvoids in the interfacial region and to improve the effective MOF loading within the selective layer. In this work, we applied a zirconium-based rigid MOF (UiO-66) to fabricate a nanocomposite hollow fibre membrane, and (–COOH) and (–NH2) modified UiO-66 were applied to investigate the effect of surface functionalization. Up to 80 wt% UiO-66 was incorporated into the thin Pebax selective layer, and both improved CO2 permeance and selectivity were obtained simultaneously with the (–NH) functionalized UiO-66. In addition, the presence of UiO-66 in Pebax significantly improved the membranes operational stability under high pressure.