Polarized micropores in a novel 3D metal-organic framework for selective adsorption properties.

A novel 3D porous metal-organic framework with 1D polarized channels was synthesized, and its adsorption properties for gas separation and chemical sensing were studied. The framework shows a preferential adsorption of CO(2) over N(2) with a selectivity of 22:1. It also exhibits a very good sensitivity to water with respect to most of the organic solvents in view of chemical sensing applications.

MOF-Mediated Interfacial Polymerization to Fabricate Polyamide Membranes with a Homogeneous Nanoscale Striped Turing Structure for CO2/CH4 Separation.

Control of the surface morphology of polyamide membranes fabricated by interfacial polymerization is of great importance in dictating the separation performance. Herein, polyamide membranes with a specific nanoscale striped Turing structure are generated through facile addition of Zr-based metal-organic framework UiO-66-NH2 in the aqueous triethylenetetramine phase. Interestingly, accompanied by the degradation of UiO-66-NH2 in aqueous solution, an intermediate complex is in situ formed through the strong interaction between the Zr metal center and the amine group from triethylenetetramine, which can lower amine diffusion and induce a local interfacial reaction, contributing to the generation of a homogeneous nanoscale striped Turing structure. The resulting membranes are used for CO2/CH4 gas separation. Compared with the parent polyamide membrane displaying a CO2/CH4 selectivity of 43.1 and a CO2 permeance of 31.5 GPU, the membrane with 0.02 wt % of UiO-66-NH2 introduced into the aqueous phase shows a higher CO2/CH4 selectivity of 58.3, along with a CO2 permeance of 27.1 GPU. Additionally, when 0.1 wt % of UiO-66-NH2 is incorporated into the aqueous phase, the membrane exhibits a combination of a higher CO2/CH4 selectivity and an enhanced CO2 permeance in contrast with the parent polyamide membrane.

Magnesium and Nitrogen Co-Doped Mesoporous Carbon with Enhanced Microporosity for CO2 Adsorption.

Mesoporous carbons (MC) have attracted a tremendous amount of interest due to their efficient molecular transport properties. However, the limited number of active sites and low microporosity generally impede their use for practical applications. Herein, we have fabricated Mg and N co-doped mesoporous carbon (Mg-NMC) with high microporosity via one-pot synthetic route followed by further steam activation. In comparison with the parent N-doped mesoporous carbon, Mg-NMC shows partially ordered mesostructure and improved CO2 adsorption capacity attributed to the introduction of basic site after Mg doping. Upon further steam activation, the microporosity is enhanced to 37.3%, while the CO2 adsorption capacity is also increased by 70.4% at 273 K and 1.0 bar.

NiCo nanoalloy encapsulated in graphene layers for improving hydrogen storage properties of LiAlH4.

NiCo nanoalloy (4-6 nm) encapsulated in grapheme layers (NiCo@G) has been prepared by thermolysis of a 3D bimetallic complex CoCo[Ni(EDTA)]2·4H2O and successfully employed as a catalyst to improve the dehydrogenation performances of LiAlH4 by solid ball-milling. NiCo@G presents a superior catalytic effect on the dehydrogenation of LiAlH4. For LiAlH4 doped with 1 wt% NiCo@G (LiAlH4-1 wt% NiCo@G), the onset dehydrogenation temperature of LiAlH4 is as low as 43 °C, which is 109 °C lower than that of pristine LiAlH4. 7.3 wt% of hydrogen can be released from LiAlH4-1 wt% NiCo@G at 150 °C within 60 min. The activation energies of LiAlH4 dehydrogenation are extremely reduced by 1 wt% NiCo@G doping.

Syntheses, structures and chemical sensing properties of three complexes with mixed ligands of carboxylate and bipyridine.

Three mixed-ligand coordination polymers, [Cu(oda)(2,2'-bipy)](2) (1), Ni(2)(oda)(2)(4,4'-bipy)·DMF (2), and [{Ni(oda)(H(2)O)(2)}(2)(µ-4,4'-bipy)]·2H(2)O (3) were synthesized and characterized. Complex 1 features a 1D chain via intermolecular π-π interactions. Complex 2 is a novel 3D microporous coordination polymer with 1D polarized channels. Complex 3 forms a 3D network via extensive hydrogen bonding interactions. Thermogravimetric analyses have been studied. The chemical sensing properties have been investigated in situ by quartz crystal microbalance (QCM). Complex 1 has a good sensitivity to toluene, complexes 2 and 3 have exceptionally high selectivity and sensitivity to water over organic solvents.

Adjustable structure transition and improved gases (H2, CO2) adsorption property of metal-organic framework MIL-53 by encapsulation of BNHx.

The structure transition of flexible MOF (MIL-53) can be adjusted by confinement of BNH(x) into MIL-53 channels. Hydrogen and carbon dioxide adsorption properties are also improved by incorporating BNH(x). At 77 K and 1 atm pressure hydrogen storage capacity can reach 2.0 wt% and CO(2) adsorption capacity is 4.5 mmol g(-1) at 273 K 1 atm.

A novel sensor based on electrochemical polymerization of diglycolic acid for determination of acetaminophen.

Diglycolic acid (DA) polymer was coated on glassy carbon (GC) electrode by cyclic voltammetry (CV) technique for the first time. The electrochemical performances of the modified electrode were investigated by CV and electrochemical impedance (EIS). The obtained electrode showed an excellent electrocatalytic activity for the oxidation of acetaminophen (ACOP). A couple of well-defined reversible electrochemical redox peaks were observed on the ploy(DA)/GC electrode in ACOP solution. Compared with bare GC electrode, the oxidation peak potential of ACOP on ploy(DA)/GC electrode moved from 0.289 V to 0.220 V. Meanwhile, the oxidation peak current was much higher on the modified electrode than that on the bare GC electrode, indicating DA polymer modified electrode possessed excellent performance for the oxidation of ACOP. This kind of capability of the modified electrode can be enlisted for the highly sensitive and selective determination of ACOP. Under the optimized conditions, a wide linear range from 2 × 10(-8) to 5.0 × 10(-4)M with a correlation coefficient 0.9995 was obtained. The detection limit was 6.7 × 10(-9)M (at the ratio of signal to noise, S/N=3:1). The modified electrode also exhibited very good stability and reproducibility for the detection of ACOP. The established method was applied to the determination of ACOP in samples. An average recovery of 100.1% was achieved. These results indicated that this method was reliable for determining ACOP.

Microporous polyimide networks with large surface areas and their hydrogen storage properties.

Microporous polyimide networks with BET surface areas up to 1407 m(2) g(-1) and pore size distribution of 4-8 Å were synthesized. The respective effect of surface area and affinity between hydrogen molecule and polyimides on hydrogen storage properties were investigated.