13 research outputs found

    Efficient Water Oxidation Using Nanostructured α‑Nickel-Hydroxide as an Electrocatalyst

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    Electrochemical water splitting is a clean technology that can store the intermittent renewable wind and solar energy in H<sub>2</sub> fuels. However, large-scale H<sub>2</sub> production is greatly hindered by the sluggish oxygen evolution reaction (OER) kinetics at the anode of a water electrolyzer. Although many OER electrocatalysts have been developed to negotiate this difficult reaction, substantial progresses in the design of cheap, robust, and efficient catalysts are still required and have been considered a huge challenge. Herein, we report the simple synthesis and use of α-Ni­(OH)<sub>2</sub> nanocrystals as a remarkably active and stable OER catalyst in alkaline media. We found the highly nanostructured α-Ni­(OH)<sub>2</sub> catalyst afforded a current density of 10 mA cm<sup>–2</sup> at a small overpotential of a mere 0.331 V and a small Tafel slope of ∼42 mV/decade, comparing favorably with the state-of-the-art RuO<sub>2</sub> catalyst. This α-Ni­(OH)<sub>2</sub> catalyst also presents outstanding durability under harsh OER cycling conditions, and its stability is much better than that of RuO<sub>2</sub>. Additionally, by comparing the performance of α-Ni­(OH)<sub>2</sub> with two kinds of β-Ni­(OH)<sub>2</sub>, all synthesized in the same system, we experimentally demonstrate that α-Ni­(OH)<sub>2</sub> effects more efficient OER catalysis. These results suggest the possibility for the development of effective and robust OER electrocatalysts by using cheap and easily prepared α-Ni­(OH)<sub>2</sub> to replace the expensive commercial catalysts such as RuO<sub>2</sub> or IrO<sub>2</sub>

    UiO-66-Coated Mesh Membrane with Underwater Superoleophobicity for High-Efficiency Oil–Water Separation

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    A UiO-66-coated mesh membrane with micro- and nanostructures was designed and successfully fabricated on steel mesh through a simple solution immersion process, exhibiting hydrophilic and underwater superoleophobic properties. It displays an outstanding oil–water separation efficiency over 99.99% with a high water permeation flux of 12.7 × 10<sup>4</sup> L m<sup>–2</sup> h<sup>–1</sup>, so high purity water (with the residual oil content less than 4 ppm) can be readily obtained from such a simple mesh membrane from various oil–water mixtures. Its large-scale membrane production will facilitate its practical usage for the industrial and environmental water purification

    Fast, Ambient Temperature and Pressure Ionothermal Synthesis of Three-Dimensional Covalent Organic Frameworks

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    Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with wide range of potential applications. However, the availability of three-dimensional (3D) COFs is still limited, and their synthesis is confined to the high-temperature solvothermal method. Here, we report for the first time a general and simple strategy to produce a series of 3D ionic liquid (IL)-containing COFs (3D-IL-COFs) by using IL as a green solvent. The syntheses are carried out at ambient temperature and pressure accompanied by a high reaction speed (e.g., only three mins for 3D-IL-COF-1), and the IL can be reused without activity loss. Furthermore, the 3D-IL-COFs show impressive performance in the separation of CO<sub>2</sub>/N<sub>2</sub> and CO<sub>2</sub>/CH<sub>4</sub>. This research thus presents a potential pathway to green large-scale industrial production of COFs

    Three-Dimensional Covalent Organic Frameworks with Dual Linkages for Bifunctional Cascade Catalysis

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    Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with broad potential applications. So far, the availability of three-dimensional (3D) COFs is limited and more importantly only one type of covalent bond has been successful used for 3D COF materials. Here, we report a new synthetic strategy based on dual linkages that leads to 3D COFs. The obtained 3D COFs show high specific surface areas and large gas uptake capacities, which makes them the top COF material for gas uptake. Furthermore, we demonstrate that the new 3D COFs comprise both acidic and basic sites, and act as excellent bifunctional catalysts for one-pot cascade reactions. The new synthetic strategy provides not only a general and versatile approach to synthesize 3D COFs with sophisticated structures but also expands the potential applications of this promising class of porous materials

    UiO-66-Coated Mesh Membrane with Underwater Superoleophobicity for High-Efficiency Oil–Water Separation

    No full text
    A UiO-66-coated mesh membrane with micro- and nanostructures was designed and successfully fabricated on steel mesh through a simple solution immersion process, exhibiting hydrophilic and underwater superoleophobic properties. It displays an outstanding oil–water separation efficiency over 99.99% with a high water permeation flux of 12.7 × 10<sup>4</sup> L m<sup>–2</sup> h<sup>–1</sup>, so high purity water (with the residual oil content less than 4 ppm) can be readily obtained from such a simple mesh membrane from various oil–water mixtures. Its large-scale membrane production will facilitate its practical usage for the industrial and environmental water purification

    UiO-66-Coated Mesh Membrane with Underwater Superoleophobicity for High-Efficiency Oil–Water Separation

    No full text
    A UiO-66-coated mesh membrane with micro- and nanostructures was designed and successfully fabricated on steel mesh through a simple solution immersion process, exhibiting hydrophilic and underwater superoleophobic properties. It displays an outstanding oil–water separation efficiency over 99.99% with a high water permeation flux of 12.7 × 10<sup>4</sup> L m<sup>–2</sup> h<sup>–1</sup>, so high purity water (with the residual oil content less than 4 ppm) can be readily obtained from such a simple mesh membrane from various oil–water mixtures. Its large-scale membrane production will facilitate its practical usage for the industrial and environmental water purification

    UiO-66-Coated Mesh Membrane with Underwater Superoleophobicity for High-Efficiency Oil–Water Separation

    No full text
    A UiO-66-coated mesh membrane with micro- and nanostructures was designed and successfully fabricated on steel mesh through a simple solution immersion process, exhibiting hydrophilic and underwater superoleophobic properties. It displays an outstanding oil–water separation efficiency over 99.99% with a high water permeation flux of 12.7 × 10<sup>4</sup> L m<sup>–2</sup> h<sup>–1</sup>, so high purity water (with the residual oil content less than 4 ppm) can be readily obtained from such a simple mesh membrane from various oil–water mixtures. Its large-scale membrane production will facilitate its practical usage for the industrial and environmental water purification

    3D Porous Crystalline Polyimide Covalent Organic Frameworks for Drug Delivery

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    Three-dimensional porous crystalline polyimide covalent organic frameworks (termed PI-COFs) have been synthesized. These PI-COFs feature non- or interpenetrated structures that can be obtained by choosing tetrahedral building units of different sizes. Both PI-COFs show high thermal stability (>450 °C) and surface area (up to 2403 m<sup>2</sup> g<sup>–1</sup>). They also show high loading and good release control for drug delivery applications

    UiO-66-Coated Mesh Membrane with Underwater Superoleophobicity for High-Efficiency Oil–Water Separation

    No full text
    A UiO-66-coated mesh membrane with micro- and nanostructures was designed and successfully fabricated on steel mesh through a simple solution immersion process, exhibiting hydrophilic and underwater superoleophobic properties. It displays an outstanding oil–water separation efficiency over 99.99% with a high water permeation flux of 12.7 × 10<sup>4</sup> L m<sup>–2</sup> h<sup>–1</sup>, so high purity water (with the residual oil content less than 4 ppm) can be readily obtained from such a simple mesh membrane from various oil–water mixtures. Its large-scale membrane production will facilitate its practical usage for the industrial and environmental water purification

    Made in Water: A Stable Microporous Cu(I)-carboxylate Framework (CityU-7) for CO<sub>2</sub>, Water, and Iodine Uptake

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    Using water as the sole solvent, the bifunctional molecule tetrakis­(methylthio)-1,4-benzenedicarboxylic acid (TMBD) was reacted with Cu­(CH<sub>3</sub>CN)<sub>4</sub>BF<sub>4</sub> to form a robust microporous metal–organic framework (MOF, CityU-7) featuring Cu­(I) ions being simultaneously bonded to the carboxyl and thioether donors. The MOF solid is stable in air and can be easily activated by heating, without the need for treatment with organic solvents. The subnanoscopic pores (ca. 0.6 nm) of the host net allow for uptake of CO<sub>2</sub> and H<sub>2</sub>O but exhibit lesser sorption for N<sub>2</sub> at 77 K. The microporous net can also be penetrated by I<sub>2</sub> molecules
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