Polyoxometalate-based metal-organic frameworks for boosting electrochemical capacitor performance

Abstract Polyoxometalate-based metal-organic frameworks (POMOFs) possess promising applications as capacitors. Herein, we report the syntheses, structures and electrochemical properties of five copper-containing POMOFs: [CuI4H2(btx)5(PW12O40)2]·2H2O (1), [CuIICuI3(H2O)2(btx)5(PWVI10WV2O40)]·2H2O (2), [CuI6(btx)6(PWVI9WV3O40)]·2H2O (3), [CuI4H2(btx)5(PMo12O40)2]·2H2O (4) and [CuIICuI3(btx)5(SiMoVI11MoVO40)]·4H2O (5) (btx = 1,4-bis(triazol-1-ylmethyl) benzene) with potential applications as capacitors. Compounds 1–3 contain the same Keggin-type polyoxometalate (POM) although with different oxidation states, allowing the analysis of the effect of the electronic population on the capacitance pe…

Two Novel Polyoxometalate-Encapsulated Metal–Organic Nanotube Frameworks as Stable and Highly Efficient Electrocatalysts for Hydrogen Evolution Reaction

Two novel polyoxometalate (POM)-encapsulated metal–organic nanotube (MONT) framework crystalline materials with unprecedented copper-mixed ligands, HUST-200 and HUST-201, have been successfully synthesized by an effective synthesis strategy. The encapsulation not only provides a shield to increase the chemical stability, but also does not affect its catalytic activity, and, therefore, the crystalline materials are very active for HER (H+ can diffuse easily through the pores of the MONTs). Remarkably, HUST-200 displays a low overpotential of 131 mV (catalytic current density is equal to 10 mA·cm–2). This work thus offers a new way for devising HER electrocatalysts with low cost using POM-enc…

Polyoxometalate Metal–Organic Frameworks: Keggin Clusters Encapsulated into Silver-Triazole Nanocages and Open Frameworks with Supercapacitor Performance

To investigate the relationship between the structures of polyoxometalate host–guest materials and their energy-storage performance, three novel polyoxometalate-based metal–organic compounds, [Ag10...

A Facile Strategy to Create Electrocatalysts of Highly Dispersive Ni–Mo Sulfide Nanosheets on Graphene by Derivation of Polyoxometalate Coordination Polymer for Advanced H2 Evolution

A High‐Capacity Negative Electrode for Asymmetric Supercapacitors Based on a PMo 12 Coordination Polymer with Novel Water‐Assisted Proton Channels

The development of a negative electrode for supercapacitors is a critical challenge for the next-generation of energy-storage devices. Herein, two new electrodes formed by the coordination polymers [Ni(itmb)4 (HPMo12 O40 )]·2H2 O (1) and [Zn(itmb)3 (H2 O)(HPMo12 O40 )]·4H2 O (2) (itmb = 1-(imidazo-1-ly)-4-(1,2,4-triazol-1-ylmethyl)benzene), synthesized by a simple hydrothermal method, are described. Compounds 1 and 2 show high capacitances of 477.9 and 890.2 F g-1 , respectively. An asymmetric supercapacitor device assembled using 2 which has novel water-assisted proton channels as negative electrode and active carbon as positive electrode shows ultrahigh energy density and power density of…

Improving the photocatalytic H2 evolution activity of Keggin polyoxometalates anchoring copper-azole complexes

Eliminating the use of precious metals as cocatalysts and using visible light are two important aspects in the field of photocatalytic H2 evolution with polyoxometalates (POMs) as photosensitizers. Here we present two new POM-based materials: [CuII5(2-ptz)6(H2O)4(GeW12O40)]·4H2O (1) and [CuI2(ppz)4][H2GeW12O40]·8H2O (2) (2-ptz = 5-(2-pyridyl) tetrazole, ppz = 3-(pyrid-4-yl) pyrazole) synthesized with the Keggin type [GeW12O40]4− (GeW12) polyanion and copper-azole complexes. The optimum photocatalytic H2 evolution rate of compound 1 without a noble metal cocatalyst is 3813 μmol g−1 h−1, which is 7.6 times higher than that of compound 2 and more than 27 times higher than that of bare GeW12 po…

CCDC 2023524: Experimental Crystal Structure Determination

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CCDC 1835308: Experimental Crystal Structure Determination

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CCDC 1851193: Experimental Crystal Structure Determination

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CCDC 1851423: Experimental Crystal Structure Determination

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CCDC 2023544: Experimental Crystal Structure Determination

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