Polyoxometalate-Incorporated Metallacalixarene@Graphene Composite Electrodes for High-Performance Supercapacitors

High-performance heterometallic photocatalysts afforded by polyoxometalate synthons for efficient H2 production

MoS2-based materials have emerged as photoelectric semiconductors characterized by a narrow band gap, high capacity for absorbing visible light, and reduced H2 adsorption energy comparable to Pt. These attributes render them appealing for application in photocatalytic hydrogen production. Despite these advantages, the widespread adoption of MoS2-based materials remains hindered by challenges associated with limited exposure to active sites and suboptimal catalytic hydrogen production efficiency. To address these issues, we have designed and synthesized a new class of highly dispersed bimetallic/trimetallic sulfide materials. This was achieved by developing polyoxometalate synthons containing Ni-Mo elements, which were subsequently reacted with thiourea and CdS. The resulting Ni3S2-MoS2 and Ni3S2-MoS2-CdS materials achieve photocatalytic hydrogen production rates of 2770 and 2873 μmol g-1h-1, respectively. Notably, the rate of 2873 μmol g-1h-1 for Ni3S2-MoS2-CdS surpassed triple (3.23 times) the performance of CdS and nearly sextuple (5.77 times) that of single MoS2. These materials outperformed the majority of MoS2-based photocatalysts. Overall, this study introduces a straightforward methodology for synthesizing bimetallic/trimetallic sulfides with enhanced photocatalytic H2 evolution performance. Our findings underscore the potential of transition metal sulfide semiconductors in the realm of photocatalysis and pave the way for the development of more sustainable energy production systems.

Six polyoxotungstate-based transition metal compounds for electrochemical capacitor application and a comparative analysis of factors affecting capacitances

Six different polyoxotungstate-based transition metal complexes were synthesized, namely [Cu5(2,2'-bpy)5(μ2-Cl)2(PO4)2(H2O)2][HPW12O40]·2H2O (1), [Cu1.5(2,2'-bpy)1.5(inic)2(H2O)1.5]3[H1.5PW12O40]2·16.25H2O (2), [Cu(2,2'-bpy)2]2[SiW12O40]·10H2O (3), [Zn(phen)3]2[PWVWVI11O40]·5H2O (4), [Zn(phen)2(H2O)]2[SiW12O40]·2H2O (5), and [Zn(2,2'-bpy)2]2[SiW12O40] (6) (2,2'-bpy = 2,2'-bipyridine, inic = isonicotinic acid, phen = 1,10-phenanthroline). Compound 1 is based on [HPW12O40]2- anions, which are accommodated within the open channels of a supramolecular network formed by novel Cu-P-Cl coordination clusters. Compound 2 is constructed from [H1.5PW12O40]1.5- and novel [Cu1.5(2,2'-bpy)1.5(inic)2(H2O)1.5]+ coordination fragments, and polyoxoanions are encapsulated within the pores created by the copper coordination fragments, resulting in a unique three-dimensional supramolecular architecture. Compound 3 is a two-dimensional structure formed through the covalent linkage between [SiW12O40]4- and [Cu(2,2'-bpy)2]2+. Compound 4 is a supramolecular architecture formed by [PWVWVI11O40]4- and [Zn(phen)3]2+ coordination fragments, while compound 5 is a supramolecular structure based on POM bi-supported Zn coordination complexes. Compound 6 is a two-dimensional framework structure constituted by [SiW12O40]4- and [Zn(2,2'-bpy)2]2+via covalent interactions. In addition, electrochemical measurement results show that the copper-based tungstate compounds 1-3 and zinc-based tungstate compounds 4-6 exhibit different performances and durabilities as electrochemical capacitors (compound 1 shows the highest specific capacitance of 94.0 F g-1 at 1.5 A g-1, whereas compound 6 maintains the best cycling stability with the capacity retention of 80.7% after 1000 cycles at 4 A g-1.). This study contributes to the development of POM-based transition metal complexes with high capacitance by providing insights into the design and synthesis process.

Highly Efficient Photocatalysts: Polyoxometalate Synthons Enable Tailored CdS-MoS2 Morphologies and Enhanced H2 Evolution

The development of photocatalysts toward highly efficient H₂ evolution reactions is a feasible strategy to achieve the effective conversion of solar energy and meet the increasing demand for new energy. To this end, we prepared two different CdS-MoS₂ photocatalysts with unique morphologies ranging from hexagonal prisms to tetragonal nanotubes by carefully tuning polyoxometalate synthons. These two photocatalysts, namely, CdS-MoS₂-1 and CdS-MoS₂-2, both exhibited remarkable photocatalytic efficiency in H₂ generation, among which CdS-MoS₂-2 showed superior performance. In fact, the best catalytic hydrogen desorption rate of CdS-MoS₂-2 is as high as 1815.5 μmol g^-1 h^-1. Such performance is superior to twice that of single CdS and almost four times that of pure MoS₂. This obvious enhancement can be accredited to the highly open nanotube morphology and highly dispersed heterometallic composition of CdS-MoS₂-2, which represents an excellent example of the highest noble-metal-free H₂ evolution photocatalysts reported so far. Taken together, these findings suggest that the development of highly dispersed heterometallic catalysts is an auspicious route to realize highly efficient conversion of solar energy and that CdS-MoS₂-2 represents a major advance in this field.

Nanomaterial with Core-Shell Structure Composed of {P2W18O62} and Cobalt Homobenzotrizoate for Supercapacitors and H2O2-Sensing Applications

Designing and preparing dual-functional Dawson-type polyoxometalate-based metal-organic framework (POMOF) energy storage materials is challenging. Here, the Dawson-type POMOF nanomaterial with the molecular formula CoK₄[P₂W₁₈O₆₂]@Co₃(btc)₂ (abbreviated as {P₂W₁₈}@Co-BTC, H₃btc = 1,3,5-benzylcarboxylic acid) was prepared using a solid-phase grinding method. XRD, SEM, TEM et al. analyses prove that this nanomaterial has a core-shell structure of Co-BTC wrapping around the {P₂W₁₈}. In the three-electrode system, it was found that {P₂W₁₈}@Co-BTC has the best supercapacitance performance, with a specific capacitance of 490.7 F g^-1 (1 A g^-1) and good stability, compared to nanomaterials synthesized with different feedstock ratios and two precursors. In the symmetrical double-electrode system, both the power density (800.00 W kg^-1) and the energy density (11.36 Wh kg^-1) are greater. In addition, as the electrode material for the H₂O₂ sensor, {P₂W₁₈}@Co-BTC also exhibits a better H₂O₂-sensing performance, such as a wide linear range (1.9 μM-1.67 mM), low detection limit (0.633 μM), high selectivity, stability (92.4%) and high recovery for the detection of H₂O₂ in human serum samples. This study provides a new strategy for the development of Dawson-type POMOF nanomaterial compounds.

Design strategy for high-performance bifunctional electrode materials with heterogeneous structures formed by hydrothermal sulfur etching

The synthesis of efficient, stable, and green multifunctional electrode materials is a long-standing challenge for modern society in the field of energy storage and conversion. To this end, we successfully synthesized five bimetallic precursor materials with excellent performance by hydrothermal reaction with the assistance of a high concentration of polyvinylpyrrolidone (PVP), and then, sulfide etched the lamellar precursor materials among them to obtain the one-dimensional heterostructured samples. Benefiting from the synergistic effect of the bimetal and the continuous electron/ion transport structure, the samples displayed excellent bifunctional activity in supercapacitor and oxygen evolution reaction (OER). Regarding supercapacitors, the exceptional performance of 2817.2 F g^-1 at 1 A g^-1 was demonstrated, while the asymmetric supercapacitors made showed an extraordinary energy density of 150.2 Wh kg^-1 at a power density of 618.5 W kg^-1 and outstanding cycling performance (94.74% capacity retention after 20,000 cycles at 10 A g^-1). Simultaneously, a wearable flexible electrode that can be wrapped around a finger was coated on a carbon cloth and was found to light up a 0.5-m-long strip of light. Moreover, it exhibited an ultralow oxygen reduction overpotential of 249 mV at 10 mA cm^-2. Hence, our work provides a facile strategy to modulate the synthesis of heterogeneous structured sulfides with a continuous electron/ion transport pathway, which possesses excellent oxygen reduction electrocatalytic performance while meeting superior supercapacitor performance. Such work provides an effective approach for the construction of multifunctional electrochemical energy materials.

POMCPs with Novel Two Water-Assisted Proton Channels Accommodated by MXenes for Asymmetric Supercapacitors

To develop high-performance supercapacitors, the negative electrode is at present viewed as one of the most challenging tasks for obtaining the next-generation of energy storage devices. Therefore, in this study, a polyoxometalate-based coordination polymer [Zn(itmb)₃ H₂ O][H₂ SiW₁₂ O₄₀ ]·5H₂ O (1) is designed and prepared by a simple hydrothermal method for constructing a high-capacity negative electrode. Polymer 1 has two water-assisted proton channels, which are conducive to enhancing the electrical conductivity and storage capacity. Then, MXene Ti₃ C₂ T_x is chosen to accommodate coordination polymer 1 as the interlayer spacers to improve the conductivity and cycling stability of 1, while preventing the restacking of MXene. Expectedly, the produced composite electrode 1@Ti₃ C₂ T_x shows an excellent specific capacitance (1480.1 F g^-1 at 5 A g^-1 ) and high rate performance (a capacity retention of 71.5% from 5 to 20 A g^-1 ). Consequently, an asymmetric supercapacitor device is fabricated using 1@Ti₃ C₂ T_x as the negative electrode and celtuce leaves-derived carbon paper as the positive electrode, which demonstrates ultrahigh energy density of 32.2 Wh kg^-1 , and power density 2397.5 W kg^-1 , respectively. In addition, the ability to illuminate a red light-emitting diode for several minutes validates its feasibility for practical application.

Impedance Analysis of Electrochemical Systems

Interpretation of impedance spectroscopy data requires both a description of the chemistry and physics that govern the system and an assessment of the error structure of the measurement. The approach presented here includes use of graphical methods to guide model development, use of a measurement model analysis to assess the presence of stochastic and bias errors, and a systematic development of interpretation models in terms of the proposed reaction mechanism and physical description. Application to corrosion, batteries, and biological systems is discussed, and emerging trends in interpretation and implementation of impedance spectroscopy are presented.

CuCoNi–S anchored CoMoO4/MoO3 forming core–shell structure for high-performance asymmetric supercapacitors

CoMoO4/MoO3@CuCoNi–S is prepared by hydrothermal and electrodeposition methods. It offers promising supercapacitor properties.

Surfactant-assisted fabrication and supercapacitor performances of a 12-phosphomolybdate-pillared metal–organic framework containing a helix and its SWNT nanocomposites

By employing a surfactant-assisted hydrothermal method, a new POMOF with a multi-fold helix was obtained, and NiPMo12/SWNTs exhibits excellent electrochemical performance and good stability as an electrode material for supercapacitors.

Defect-Engineered NiCo-S Composite as a Bifunctional Electrode for High-Performance Supercapacitor and Electrocatalysis

Defect engineering is a reasonable solution to improve the surface properties and electronic structure of nanomaterials. However, how to introduce dual defects into nanomaterials by a simple way is still facing challenge. Herein, we propose a facile two-step solvothermal method to introduce Fe dopants and S vacancies into metal-organic framework-derived bimetallic nickel cobalt sulfide composites (NiCo-S). The as-prepared Fe-doped NiCo-S (Fe-NiCo-S) possesses improved charge storage kinetics and activities as electrode material for supercapacitors and the oxygen evolution reaction (OER). The obtained Fe-NiCo-S nanosheet has a high specific capacitance (2779.6 F g^-1 at 1 A g^-1) and excellent rate performance (1627.2 F g^-1 at 10 A g^-1). A hybrid supercapacitor device made of Fe-NiCo-S as the positive electrode and reduced graphene oxide (rGO) as the negative electrode presents a high energy density of 56.0 Wh kg^-1 at a power density of 847.1 W kg^-1 and excellent cycling stability (capacity retention of 96.5% after 10,000 cycles at 10 A g^-1). Additionally, the Fe-NiCo-S composite modified by Fe doping and S vacancy has an ultralow oxygen evolution overpotential of 247 mV at 10 mA cm^-2. Based on the density functional theory (DFT) calculation, defects cause more electrons to appear near the Fermi level, which is conducive to electron transfer in electrochemical processes. Our work provides a rational strategy for facilely introducing dual defects into metal sulfides and may provide a novel idea to prepare electrode materials for energy storage and energy conversion application.

Three Polyoxovanadates-Based Organic-Inorganic Hybrids: Structural Variation, Bifunctional Electrocatalytic Activities, and Computational Studies

Three bimetallic organic-inorganic hybrids based on the [V₂O₆]^2- building unit, [Cu(pty)(V₂O₆)]·H₂O (1), [Cu(pty)(V₂O₆)] (2), [Cu(tpy)(V₂O₆)] (3), (pty = 4'-(4″-pyridyl)-2,2':6',2″-terpyridine, tpy = 2,2':6',2″-terpyridine), were synthesized via a one-pot method. Hybrid 1 has a 1D straight chain architecture with [V₂O₆]^2- clusters and Cu-pty complexes; hybrids 2 and 3 possess a 2D sheet structure including 10-membered rings assembled from four [Cu(pty)]²⁺ motifs and six [V₂O₆]^2- clusters in 2, and two [Cu(tpy)]²⁺ units and eight [V₂O₆]^2- clusters in 3. Noteworthy, hybrids 1-3 can be employed as bifunctional electrocatalysts for electroreduction of nitrite and electrooxidation of ascorbic acid. Additionally, theoretical calculations including the molecular electrostatic potential and the frontier molecular orbital were performed to estimate the electronic structure of hybrids 1-3. The natural bond orbital analysis was also calculated to interpret the electron charge distribution.

Polyoxometalate-Templated Cobalt-Resorcin[4]arene Frameworks: Tunable Structure and Lithium-Ion Battery Performance

By employing a bowl-like tetra(benzimidazole)resorcin[4]arene (TBR4A) ligand, two new polyoxometalate-templated metal-organic frameworks (POMOFs), [Co₈Cl₁₄(TBR4A)₆]·3[H_3.3SiW₁₂O₄₀]·10DMF·11EtOH·20H₂O (1) and [Co₃Cl₂(TBR4A)₂(DMF)₄]·[SiW₁₂O₄₀]·2EtOH·3H₂O (2), have been prepared under solvothermal conditions (DMF = N,N'-dimethylformamide). 1 shows a 2D cationic layer, whereas 2 exhibits a 3D framework. Remarkably, the Keggin POMs in 1 and 2 were located in the cavities formed by two bowl-like resorcin[4]arenes in sandwich fashions. Their framework structures were highly dependent on the coordination modes of the TBR4A ligands. To increase the conductivity of POMOFs, the samples of 1 and 2 were loaded on the conductive polypyrrole-reduced graphene oxide (PPy-RGO) via ball milling (1@PG and 2@PG). Then, the obtained composites experienced calcination at a proper temperature to produce 1@PG-A and 2@PG-A. The resulting 1@PG-A and 2@PG-A composites, with improved conductivities, uniform sizes and micropores, exhibited promising electrochemical performance for lithium-ion batteries. We herein proposed a size-controlled route for the rational fabrication of functional POMOFs and their usage in energy fields.

Adhesion of Grafted-to Polyelectrolyte Brushes Functionalized with Calix[4]resorcinarene and Deposited as a Monolayer

Polyelectrolyte adhesives, either poly[2-(dimethylamino)ethyl methacrylate] or poly(methacrylic acid), functionalized with a surface-active calix[4]resorcinarene were grafted onto silicon wafers. Adhesion studies on these grafted-to brushes using polyelectrolyte hydrogels of opposite charge showed that it is the calix[4]resorcinarene, rather than adsorption of polyelectrolyte monomers, that adheres the brush to the silicon substrate. The adhesion measured was similar to that measured using polymers grafted from the surface, and was stronger than a control layer of poly(vinyl acetate) under the same test conditions. The limiting factor was determined to be adhesive failure at the hydrogel-brush interface, rather than the brush-silicon interface. Therefore, the adhesion has not been adversely affected by changing from a grafted-from to a grafted-to brush, demonstrating the possibility of a one-pot approach to creating switchable adhesives.

A High-Capacity Negative Electrode for Asymmetric Supercapacitors Based on a PMo12 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 23.4 W h kg^-1 and 3864.4 W kg^-1 , respectively. Moreover, the ability to feed a red light emitting diode (LED) also demonstrates the feasibility for practical use. The results allow a better elucidation of the storage mechanism in polyoxometalate-based coordination polymers and provide a promising direction for exploring novel negative materials for new-generation high-performance supercapacitors.

Two Ni/Co-substituted sandwich-type germanomolybdates based on an unprecedented trivacant polyanion [α-GeMo10O36]8

Two Ni/Co-substituted sandwich-type germanomolybdates, {[M₃(NH₂-trz)₆(H₂O)₆][M₄(H₂O)₂(HGeMo₁₀O₃₆)₂]}·nH₂O (M = Ni²⁺ (1) and Co²⁺ (2), n = 10 (1) or 11 (2), NH₂-trz = 4-amino-1,2,4-triazole), have been obtained under hydrothermal conditions. 1 and 2 represent the first trivacant Keggin germanomolybdates involving unprecedented [α-GeMo₁₀O₃₆]^8- fragments and {M₃O₄} quasi-cubane building units. Both of them exhibit electrocatalytic behaviours for H₂O₂ reduction and photocatalytic properties for CO₂ conversion.

3D silk fibroin/carbon nanotube array composite matrix for flexible solid-state supercapacitors

Silk fibroin decorates CNTA to form 3D microporous N-doped carbon frameworks for high-performance supercapacitors with high flexibility and wettability.

A polyoxometalate-encapsulated nanocage cluster organic framework built from {Cu4P2} units and its efficient bifunctional electrochemical performance

The first polyoxometalate-encapsulated twenty-four-nucleus organophosphorus-copper nanocage cluster organic framework has been constructed and it is shown to exhibit highly efficient bifunctional electrochemical performance.

Four novel Zn(ii)/Cu(ii) coordination polymers containing hydroxyl groups: synthesis, crystal structure, luminescence sensing and photocatalysis properties

CPs 1, 3 and 4 show a 2D network, while 2 possesses a 3D network. 1 is a highly selective and sensitive bifunctional luminescent sensor towards Cu²⁺ and Cr₂O₇²⁻ ions. 3 and 4 exhibit photocatalytic activities for degradation of dyes (MB/MO).

Four Keggin-based compounds constructed by a series of pyridine derivatives: synthesis, and electrochemical, photocatalytic and fluorescence sensing properties

Four compounds based on Keggin anions and Ag^I ions were obtained, the photocatalytic and electrochemical properties were studied. Compound 4 can act as a Hg²⁺ fluorescence sensor.

Syntheses, Crystal Structure, Electrocatalytic, and Magnetic Properties of the Monolanthanide-Containing Germanotungstates [Ln(H2O) n GeW11O39]5- (Ln = Dy, Er, n = 4,3)

Two monolanthanide-containing polyanions based on monolacunary Keggin germanotungstates [Ln(H2O) n GeW11O39]5- (Ln = Dy, Er, n = 4,3) have been synthesized in simple one-pot synthetic procedure and compositionally characterized in solid state by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. Electronic absorption and emission spectra of the title compounds in solution were also studied. The [DyIII(H2O)4GeW11O39]5- Keggin POM exhibits a slow relaxation of magnetization. The cyclic voltammetry measurements and mass spectrometry were carried out to check the stability of the compounds in solution. Both polyanions prove efficient in the electrocatalytic reduction of nitrite. To our knowledge, this observation establishes the first example of electrocatalysis of nitrite reduction by all inorganic monolanthanide-containing germanotungstates family.

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(C₂H₂N₃)₈][HVW₁₂O₄₀], [Ag₁₀(C₂H₂N₃)₆][SiW₁₂O₄₀], and [Ag(C₂H₂N₃)][Ag₁₂(C₂H₂N₃)₉][H₂BW₁₂O₄₀] are synthesized by a one-step hydrothermal method and further confirmed by single-crystal X-ray diffraction analyses and other numerous characterization techniques. In compound [Ag₁₀(C₂H₂N₃)₈][HVW₁₂O₄₀], the Keggin clusters are intersected into channels formed by a 3D open metal-organic framework. In contrast, in compounds [Ag₁₀(C₂H₂N₃)₆][SiW₁₂O₄₀] and [Ag(C₂H₂N₃)][Ag₁₂(C₂H₂N₃)₉][H₂BW₁₂O₄₀], the Keggin clusters are encapsulated into silver-triazole metal-organic nanocages to construct core-shell structures, which are further fused together by covalent bonds to form 3D polyoxometalate-based metal-organic frameworks. The electrochemical properties of three compound-based electrodes are estimated by cyclic voltammetry, galvanostatic charge-discharge, electrochemically active surface area, and electrochemical impedance spectroscopy. The results of the electrochemical performance tests indicate that these compounds possess high specific capacitance and cycling stability, especially [Ag₁₀(C₂H₂N₃)₈][HVW₁₂O₄₀], showing a specific capacitance of 93.5 F g^-1, which is higher than that of many other polyoxometalate-based electrode materials. A possible mechanism of the electrochemical performance is explored, which is mainly related to the redox capacity of polyoxometalate, the electrochemically active surface area, the electrochemical impedance spectroscopy, and the microstructures of polyoxometalate-based metal-organic frameworks.

Redox Tuning in Crystalline and Electronic Structure of Bimetal-Organic Frameworks Derived Cobalt/Nickel Boride/Sulfide for Boosted Faradaic Capacitance

The development of efficient electrode materials is a cutting-edge approach for high-performance energy storage devices. Herein, an effective chemical redox approach is reported for tuning the crystalline and electronic structures of bimetallic cobalt/nickel-organic frameworks (Co-Ni MOFs) to boost faradaic redox reaction for high energy density. The as-obtained cobalt/nickel boride/sulfide exhibits a high specific capacitance (1281 F g^-1 at 1 A g^-1 ), remarkable rate performance (802.9 F g^-1 at 20 A g^-1 ), and outstanding cycling stability (92.1% retention after 10 000 cycles). An energy storage device fabricated with a cobalt/nickel boride/sulfide electrode exhibits a high energy density of 50.0 Wh kg^-1 at a power density of 857.7 W kg^-1 , and capacity retention of 87.7% (up to 5000 cycles at 12 A g^-1 ). Such an effective redox approach realizes the systematic electronic tuning that activates the fast faradaic reactions of the metal species in cobalt/nickel boride/sulfide which may shed substantial light on inspiring MOFs and their derivatives for energy storage devices.

A Giant Mo/Ta/W Ternary Mixed-Addenda Polyoxometalate with Efficient Photocatalytic Activity for Primary Amine Coupling

The reactivity and properties of polyoxometalates (POMs) vary remarkably as a function of the kind of addenda atoms, so the design and synthesis of new mixed-addenda POMs is a promising approach for the further development of the POM-related areas. In the present work, the first Mo/Ta/W ternary mixed-addenda POM (NH₄)₄₁H₇[K₃(H₂O)₃(P₂W₁₅Ta₃O₆₂)₆(Mo₂O₄CH₃CO₂)₃(MoO₃)₂]·85H₂O (1), which is composed of 6 {P₂W₁₅Ta₃O₆₂} linked by 3 {Mo^V₂O₄(OOCCH₃)⁺} and 2 {Mo^VIO₃} via 18 novel Mo-O-Ta bridges has been synthesized. The precursor {P₂W₁₅Ta₃}, which has lower redox potential, is crucial for the formation of 1. The red-brown solid sample of 1 shows strong absorption in the visible region. The visible-light responsive charge transfer from benzylamine to 1 was observed experimentally. 1 was proved to be an efficient photocatalyst under simulated sunlight (AM 1.5G) radiation for the oxidative coupling of primary amines to imines using atmospheric O₂.

Rational design, crystal structures and sensing properties of a series of luminescent MOFs based on a flexible tetracarboxylate ligand and N-donor ligands

Six Zn/Cd MOFs were synthesized and characterized. 1–3 are 1D ring chains. 4–5 show 2D bilayer network. 6 possesses a 3D network structure. In particular, 2 demonstrates highly selective and sensitive luminescent sensor towards acetone and Fe³⁺ ion.

Mo-Based crystal POMOFs with a high electrochemical capacitor performance

The capacitor performance of newly synthesized crystalline POMOFs was higher than those of the majority of reported POMOF-, state-of-the-art MOF- and POM-based materials.

Four new dual-functional electro-catalysts formed from small molybdenum clusters and Cu-pyridyl complexes

Four new isopolymolybdates-based organic–inorganic hybrids decorated with Cu-pyridyl complexes were prepared by using one-pot methods. Compounds 1–4 display discrepant dual-functional electro-catalytic activities toward reduction of nitrite and oxidation of ascorbic acid.