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Developing carbon-based materials with high catalytic performance and sensitivity has significance in low-cost and highly efficient nanozymes. Herein, for the first time, Cu,N-codoped hollow carbon nanospheres (CuNHCNs) with highly active Cu-Nx sites were successfully assembled through a template-free strategy, in which Cu

A novel integrated nanozyme (FeMo6@CeO2) is synthesized. It was found that the effect on the substrate adsorption capacity due to specific surface area was more significant than active site exposure for cascade mimetic enzyme activity.

A ternary MIL-100(Fe)@PMo12@3DGO nanocomposite was designed and fabricated, which exhibits excellent peroxidase-like activity and the lowest limit of detection (0.14 μM) for glucose.

Although many satisfactory studies have been developed for biomolecule detection, the complexity of biofluids still poses a major challenge to improve the performance of nanomaterials as electrochemical sensors. Herein, unprecedented polyoxometalate-based metal-organic frameworks (POMOFs) with 8-fold meso-helical feature, [Ag5(trz)4]2[PMo12O40] (PAZ), were synthesized and explored as electrochemical sensors to detect dopamine (DA). To improve the conductivity of PAZ and the binding ability with single-walled carbon nanotubes (SWCNTs), the nanocomposite of carboxyl functionalized SWCNTs (SWCNTs-COOH) with nano-PAZ (NPAZ), NPAZ@SWCNTs-COOH, was fabricated, and transmission electron microscopy (TEM) shows that NPAZ can interact stably and uniformly with SWCNTs-COOH, owing to more defect sites on the surface of SWCNTs-COOH. The electrochemical result of NPAZ@SWCNTs-COOH/GCE towards detecting DA shows that the linear range was from 0.05 to 100 μM with a detection limit (LOD) of 8.6 nM (S/N = 3).

Developing highly active and sensitive peroxidase mimics for L -cysteine (L -Cys) colorimetric detection is very important for biotechnology and medical diagnosis. Herein, polyoxometalate-doped porous Co3 O4 composite (NiMo6 @Co3 O4 ) was designed and prepared for the first time. Compared with pure and commercial Co3 O4 , NiMo6 @Co3 O4 (n) composites exhibit the enhanced peroxidase-mimicking activities and stabilities due to the strong synergistic effect between porous Co3 O4 and multi-electron NiMo6 clusters. Moreover, the peroxidase-mimicking activities of NiMo6 @Co3 O4 (n) composites are heavily dependent on the doping mass of NiMo6 , and the optimized NiMo6 @Co3 O4 (2) exhibits the superlative peroxidase-mimicking activity. More importantly, a sensitive L -Cys colorimetric detection is developed with the sensitivity of 0.023 μM-1 and the detection limit at least 0.018 μM in the linear range of 1-20 μM, which is by far the best enzyme-mimetic performances, to the best our knowledge.

Anderson-type polyoxometalate containing Fe3+ and Mo6+, (NH4)3[H6Fe(III)Mo6O24] (FeMo6), was found to work as an oxidase-mimicking nanoenzyme for the first time, exhibiting the ability of catalytic oxidation of o-phenylenediamine (OPD), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTs), and 3,3′,5,5′-tetramethylbenzidine (TMB), which features easy synthesis, low cost, simple operation, and low consumption. Attributed to the nature of FeMo6 and Fenton-like effect, a novel sensor based on two consecutive “turn on” fluorescence was developed for detecting dopamine (DA) by employing the FeMo6-OPD system, and the linear range was from 1 to 100 μM with the detection limit 0.0227 μM (3σ/s). Moreover, to increase oxidase-mimic activity of FeMo6, reduced graphene oxide (rGO) loading FeMo6 composites (FeMo6@rGO (n), n = 5%, 10%, 15%) was fabricated, and results show that oxidase-like activities of FeMo6@rGO (n) are dependent on the mass ratio of FeMo6/rGO, and FeMo6@rGO (10%) exhibits the highest oxidase-mimic activity and the fastest respond time (4 min) among all reported oxidase mimic of DA to date.

A new [Cu2bix2] sub-ring modifying Wells–Dawson polyoxometalates (POMs) compound containing, H10[Cu(bix)2(P2W18O62)2](bix)6·16H2O (CubixP2W18) (bix = 1,4-bis(imidazol-1-ylmethyl)benzene), has been synthesized, characterized and studied as electrochemical biosensor for detecting uric acid (UA) for the first time in the work. Interesting is that CubixP2W18 contain fascinating left- and right-helical chain. Moreover, the CubixP2W18 modified glassy carbon electrodes (GCE) shows excellent electrochemical activities and higher selectivity and stabilization toward UA. The linear response range is from 2.5 × 10−7 M to 6.79 × 10−4 M and the lower detection limit is as low as 4.97 × 10−7 M (S/N = 3). The strategy of employing Wells–Dawson POMs-based sensors provides a new pathway to design new sensor for detecting UA in the field of sensor and medical diagnosis.

Four polyoxometalate (POM)-based Cu complexes with the hydroxylated pyridine analogue 3-(2-hydroxylpyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl (btpo), H3{[Cu2(btpo)2](PW12O40)}·2H2O (1), H3{[Cu2(btpo)2](PMo12O40)}·2H2O (2), H2{[Cu2(btpo)2](SiW12O40)·SO4 (3), and H4{[Cu4(btpo)4](SiW12O40)}·8H2O (4), were synthesized hydrothermally under acid conditions. Single-crystal X-ray structural analysis reveals that 3-(pyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl was hydroxylated into btpo in compounds 1-4, again providing structural evidence for the Gillard mechanism, in which H2O as a weak nucleophile can attack the α-C atom of N-heterocyclic molecules at a lower pH value (ca. 1.0) with the help of POMs.

Two new complexes based on pipemidic acid (HPPA) and Co2+/Cd2+ ions, [Co(PPA)2]·2H2O (1) and Cd(PPA)2 (2), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis shows that complexes 1 and 2 exhibit similar structures containing two-fold meso-helices and 1D supramolecular channels. The interaction of calf-thymus (CT-DNA) with complexes 1 and 2 with was explored by UV spectrum, and competitive studies with ethidium bromide (EB) by fluorescence spectrum. Notably, these results indicate that complexes 1 and 2 possess the higher binding DNA affinity than free HPPA drugs, maybe attributed to the coordinated metal ions and the helical channels. And the resultant hypochromism suggests the tight binding of 1 and 2 with CT-DNA probably by the intercalative mode. Moreover, the relatively high Ksv value also indicates that 1 and 2 can bind to CT-DNA for the intercalative binding sites. Two new complexes based on HPPA were synthesized and structural description, and exhibit similar structures containing two-fold meso-helices. The result of the interaction with CT-DNA indicates that complexes can bind to the CT-DNA by the intercalative mode and possess the higher binding constant to CT-DNA than free HPPA drugs.

To address the poor cycling stability and low rate capability of MoS

Introducing the idea of integrated design and cascade activity into nanozyme, the novel integrated nanozymes (INAzymes), FeMo

Reactions of N,2-dihydroxy-3-methoxybenzamide (H3L) with transition metal acetates in the presence of pyridine and/or 2,2′-bipyridine under solvothermal conditions give two pentanuclear complexes, ...

To improve the electrochemical performances and to understand the mechanism of lithium storage of polyoxometalate-based metal–organic frameworks (POMOFs), a generic strategy to construct nanocompos...

Developing a new cost-effective and reliable approach used for the detection of uric acid (UA) with no requirement of uricase is still very challenging. Herein, an easily realized, cost-effective, and uricase-free approach is reported for selective colorimetric biosensing of UA utilizing polypyrrole (PPy)-coated polyoxometalate-encapsulated fourfold helical metal-organic frameworks Ag5[bimt]2[PMo12O40]·2H2O (Ag5PMo12) as a monolithic peroxidase mimic. It is demonstrated that the as-obtained Ag5PMo12@PPy possesses excellent peroxidase-like activity originated from the synergistic effect to induce catalytic oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to green oxTMB in the presence of H2O2. Then, the green oxTMB can be selectively converted to colorless TMB induced by UA; thus, UA can inhibit the catalytic oxidation of TMB. Based on these results, a uricase-free colorimetric biosensor for UA is achieved with a linear detection range of 1-50 μM and a detection limit of 0.47 μM. More importantly, the developed biosensor is suited for simple-operated and good reliable UA detection in clinical samples, showing promising application ability in clinical diagnosis and relative fields.

Rechargeable lithium-ion batteries (LIBs) for potentially low-cost and high-energy-density storage have been intensively researched to meet ever-growing demands. Achieving higher storages and understanding the transporting and storing diffusion process of Li ions are still great challenges. Herein, a porous crystalline polyoxometalate-based metal–organic framework (POM@MOF), H2[CuII4(Htrz)5(H2O)2][MoVI4CuII4O26]0.5·3H2O, with defect sites as a LIB electrode material is reported. The Li-ion diffusion process in the material was investigated using ex situ X-ray photoelectron spectroscopy (XPS) and off-line powder X-ray diffraction (PXRD), indicating that O atoms of POM nano-clusters can be regarded as Li-ion acceptors (storage sites); meanwhile the defect sites (uncoordinated N atoms or –N–H groups) in the crystalline material also participate in the Li-ion storage. The reported porous crystalline POM@MOF material with defects delivers a remarkable Li-ion storage capacity of ca. 700 mA h g−1 in 200 cycles at a current density of 100 mA g−1.

A new polyoxometalate (POM) pillared metal–organic framework (POMOF), [Cu24(Trz)16(H2O)Cl4(HPMo12O40)] (Cu-POM, Trz = 1,2,3-triazole), was synthesized and characterized. Crystal analysis reveals that the Keggin POMs are inserted into copper–triazole layers with a graphite-like structure generating a POM-supported porous three-dimensional framework. Owing to the combination of the multi-electron redox property of POM units and the open porous framework, Cu-POM can be utilized as an anode material for lithium ion batteries (LIBs), and exhibits a reversible capacity of 525 mA h g−1 at a current density of 100 mA g−1 after 100 cycles. Moreover, to illustrate lithium storage, the impedance spectra of compound Cu-POM during the first and 100th charge process have also been studied. The study of Cu-POM in this work might guide the development of POM-based electrode materials for LIBs.

The application of surfactant or surfactant-assisted media to grow polyoxometalate (POM)-based MOFs (POMOFs) is extremely scarce. In this work, for the first time, we use water-polyethylene glycol (PEG) 400 mixed media to synthesize two new crystalline POM-pillared three-dimensional porous arrays, [Co7(Trz)12(H2O)8][HPX12O40(VO)2]·12H2O (X = Mo for Co-PMo and X = W for Co-PW, Trz = 1,2,4-triazole). By employing a simple sonication-driven functionalization strategy, Co-PMo/CNTs (PCNT-n) nanocomposites with increased effective sites, enhanced specific surface area and excellent conductivity are fabricated. The resulting PCNT-2 nanocomposite shows an excellent reversible capacity of 820 mA h g−1 after 100 cycles and outstanding rate capability as an anode for lithium batteries. After the initial decay, the PCNT-2 electrode can bear a current density of 2000 mA g−1 over 450 cycles without obvious capacity loss. Meanwhile, the mechanism of lithium storage in PCNT-2 is discussed using X-ray photoelectron spectroscopy (XPS). Moreover, the PCNT-2 nanocomposite exhibits the hybrid behavior of battery and supercapacitor according to the electrochemical kinetic analyses. This might open new avenues for the design of crystalline POM-based materials or their nanocomposites to achieve high-performance energy storage.

In order to explore novel colorimetric biosensors with high sensibility and selectivity, two new Keggin polyoxometalates (POMs)-based Cu-trz (1,2,4-triazole) metal-organic frameworks (MOFs) with suitable specific surface areas and multiple active sites were favorably fabricated; then single-walled carbon nanotubes (SWNTs) were merged with new POMOFs to construct POMOF/SWNT nanocomposites. Herein, POMOF/SWNT nanocomposites as peroxidase mimics were explored for the first time, and the peroxidase-mimicking activity of the prepared POMOF/SWNT nanocomposites is heavily dependent on the mass ratio of POMOFs and SWNTs, in which the maximum activity is achieved at the mass ratio of 2.5:1 (named PMNT-2). More importantly, PMNT-2 exhibits the lowest limit of detection (0.103 μM) among all reported materials to date and the assumable selectivity toward l-cysteine (l-Cys) detection. With these findings, a convenient, sensitive, and effective "on-off switch" colorimetric platform for l-Cys detection has been successfully developed, providing a promising prospect in the biosensors and clinical diagnosis fields.

Polyoxometalate-based crystalline materials as electro-active medium have exhibited excellent performances as bio/chemical sensors, particularly when synergy is reached upon combining with conductive materials. In this study, a catenane Keggin-type phosphomolybdic acid-based Ag-triazole framework and reduced graphene oxide (PMo12[6]catenane/rGO) was synthesized and employed to fabricate a modified electrode to detect the neurotransmitter dopamine (DA). Results show that PMo12[6]catenane and rGO composite modified electrode had strong catalytic activity for oxidation of DA and exhibited wide linear detection range from 1 to 90 μM with the limit of detection (LOD) of 0.890 μM and 1–44 μM with LOD 0.065 μM (S/N = 3). No interference from uric acid (UA) and ascorbic acid (AA) demonstrates that PMo12[6]catenane and rGO composite modified electrode possesses good selectivity to DA detection. The work can promote the further development of POMOFs with different structures in sensing applications.

A new 12-tungstovanadate-templated 3D nanocage framework, Ag10(μ4-ttz)4(H2O)4(VW12O40) (VW12@MOCF), was designed based on a “molecular library”, hydrothermally synthesized, structurally characteriz...

For the sake of effective colorimetric sensing-pattern, a sensitive colorimetric sensor was conceived based on polyoxometalates based metal-organic frameworks (POMOFs) and polydiallyldimethylammonium chloride functionalized reduced graphene oxide (PDDA-rGO) for the first time, in which PDDA as a “glue” molecule turns rGO nanosheets into general platforms for bonding POMOFs nanoparticles. Herein, a new POMOF compound with fascinating helices-on-helices feature, [Ni4(Trz)6(H2O)2][SiW12O40].4H2O (Trz = 1,2,4-triazole) (abbreviated as Ni4SiW12), was synthesized and characterized, then PDDA-rGO sheet as dispersive and conductive material was successfully introduced to Ni4SiW12 fabricating new PDDA-rGO/Ni4SiW12-n nanocomposites, (abbreviated as PMPG-n). The resulting PMPG-n nanocomposites as peroxidase mimetic show excellent catalytic activities under extreme condition (pH value 2.5), attributed to the nature and synergies from POMs, MOFs and PDDA-rGOs. Note that the peroxidase-like activity of PMPG-1 (the mass ratio of Ni4SiW12 to PDDA-rGO is 1:1) exhibits higher sensitivity (1–60 μM), faster response (10 min) and the lowest limit of detection (2.07 μM) among all reported materials to citric acid (CA) to date. This work opens up new application prospects in colorimetric sensing system for food quality control and safety, biotechnology and clinical diagnosis.

To explore a novel colorimetric biosensor with high sensibility and selectivity, a new Wells–Dawson-type polyoxometalate (POM)-based metal–organic framework (MOF) with an eightfold helix, [Cu9(FKZ)12(H2O)8][H3P2W18O62]2·4H2O (CuFKZP2W18) (HFKZ = 1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-1-yl)methyl] ethanol), was successfully synthesized; then, polypyrrole (PPy) was introduced to fabricate CuFKZP2W18/PPy(n) nanocomposites (n = 7%, 15%, 30%) via a facile in situ oxidation polymerization process. All the results indicate that CuFKZP2W18/PPy(15%) as a colorimetric biosensor exhibits lower limits of detection (0.07 μM towards H2O2 and 0.627 μM towards ascorbic acid), smaller Km values (0.106 mM for H2O2 and 0.042 mM for o-phenylenediamine) and higher sensitivity (0.0227 1 μM−1 towards H2O2 and 0.0025 1 μM−1 to ascorbic acid) than most reported enzyme mimetics to the best of our knowledge.

A new polyoxometalate (POM)-templated 3-D copper(II)-triazole framework [Cu10(trz)10(OH)6(Cl)4][H3PW12O40]·2H2O (trz = 1,2,3-triazole) has been synthesized and characterized by single crystal X-ray diffraction and other routine methods. The 3-D POM/copper(II)-triazole hybrid framework with a 1-D channel possesses a pcu topology under the template of bulk Keggin-type phosphotungstate. As a new kind of peroxidase mimetic, the new compound effectively catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. The electrostatic interactions and hydrogen bonds/π-π stacking interactions among TMB, trz, and phosphotungstate are responsible for the enhancement of peroxidase-like activity. In addition, application for colorimetric sensing of H2O2 is also explored; the new compound exhibits a wide linear range (1–80 μM), low detection limit (0.21 μM), and fast response (2 min).

A new fluconazole-functionalized polyoxometalate-based metal-organic framework (POMOF) [Ag3(FKZ)2(H2O)2][H3SiW12O40] (AgFKZSiW12) was successfully constructed, and its polypyrrole (PPy) coated composite AgFKZSiW12@PPy was also obtained via a facile 'in situ' oxidation polymerization process. The peroxidase-like activity evaluation indicates that the maximized synergistic effect from the integration of PPy, SiW12 clusters, HFKZ drug molecules, and Ag ions deeply enhanced the overall performance. More importantly, AgFKZSiW12@PPy exhibits the fastest response time (30 s) among all the reported peroxidase mimics to date, including the pristine AgFKZSiW12 (2 min). Moreover, the AgFKZSiW12@PPy-based colorimetric biosensing platform towards H2O2 and ascorbic acid (AA) exhibits limits of detection (LOD) as low as 0.12 μM and 2.7 μM, respectively. This work reveals a promising prospect in medical diagnosis and biotechnology for colorimetric biosensor fabrication with high performance through the introduction of PPy.

Herein, a novel Ce3+ self-doped CeOx/FeOCl composite was successfully prepared by a facile method for the first time, which showed remarkable catalytic activity as a Fenton catalyst in the degradation of phenol under the conditions of a neutral solution, room temperature and natural light. In CeOx/FeOCl, 5.23% CeOx is the optimal condition, and the degradation constant (k) of CeOx/FeOCl is greater than that of FeOCl by a factor of 10.8. CeOCl in the composite plays a more important role than CeO2, which greatly increases the production of ˙OH radicals. Furthermore, the Ce-doping in FeOCl accelerates the separation efficiency of the photogenerated electron-hole pairs. The increased surface area and surface potential of CeOx/FeOCl than those of FeOCl effectively promote the adsorption of phenol, which is 4.05 times that of FeOCl. According to the DFT calculations, the Ce-doping in FeOCl enhances the structural stability by increasing the strength of the chemical bonds. The adsorption of H2O2 with Ce3+ is energetically favorable, which promotes the production of ˙OH radicals. A synergistic mechanism for the enhanced catalytic performance of CeOx/FeOCl is proposed.

Here, a new three-dimensional molybdate-based metal-organic framework (MOF), [Zn3(MoO4)2(trz)2(H2O)2] (1), (trz = 1,2,4-triazole) was successfully prepared by the surfactant-thermal method for the first time. Single crystal X-ray diffraction analysis reveals that the new compound possesses twofold meso-helical structure fabricated by Zn ions and trz ligand, and the inorganic MoO4-Zn nets insert into the helix arrays. In addition, Zn ions as their common junction stabilize the whole framework. As a kind of new peroxides mimic enzyme, the new compound can effectively catalyze the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, accompanied by a obvious color varvation of solution (1 min responsed time). Moreover, the result of colorimetric sensing of H2O2 is that the H2O2 detection limit is 0.25 μM, and the linear range is 1 to 80 μM.

A stable polyoxometalate (POM)-pillared metal–organic framework (MOF) with 6-nuclear Cu-pz and 10-nuclear Cu-pz-Cl cycles, [Cu5(pz)6Cl][SiW12O40] (CuSiW12) (pz = pyrazine), has been hydrothermally synthesized and structurally characterized. Inspired by the reported horseradish peroxidase (HRP) and other enzyme mimics, the peroxidase-like activity of CuSiW12 was investigated in detail to catalyze the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, which exhibits excellent peroxidase-like activity than that of pristine silicotungstic acid. Moreover, the detection of H2O2 was also studied in the TMB/CuSiW12/H2O2 system, which exhibits good sensitivity, wide linear range (1–60 μM), the lowest detection limit (0.10 μM) and faster response time towards H2O2 (2 min) to date, to the best our knowledge, maybe due to the maximized synergistic effects of SiW12 clusters, pyrazine molecules, Cu ion and the stable structure.

Two Keggin polyoxometalate (POMs) based hybrid compounds containing helix/nanocages as peroxidase-like mimics have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis reveals that compound 1 exhibits a POM-pillared framework with open nanotube channels (ca. 5.6 × 5.8 A2), in which SiW12 polyanions are sandwiched between the adjacent Cu-fkz sheets with meso-helix. And an unprecedented twisted octahedral hexamer nanocage (ca. 10 × 10 A2) is observed in compound 2. Compared with the other POMs involved peroxidase-like mimics, both compounds 1 and 2 exhibit higher peroxidase-like catalytic activities, broader applications range, faster respond time and lower detection limit, which maybe attribute to the maximized synergistic effects of SiW12 clusters, fkz molecules, metal ions and the distinct structure. Based on the facts, compounds 1 and 2 as enzyme mimics might expand their application around physiological pH conditions, and can be used as one kind of effective probe to detect H2O2 in live organism.

A new polyoxometalate based hybrid compound containing Ag-Ag chain, [Ag29(trz)18][SiWV7WVI5O40] (Ag29SiW12), was synthesized by the simple one-step hydrothermal reaction of silver nitrate, 1, 2, 3- triazole (trz), and [SiW12O40]4- polyanion. Single crystal X-ray diffraction analysis shows that the [SiW12O40]4- polyanions as coordinating guests were successfully encapsulated into the metal-organic framework host matrix. The Keggin [SiW12O40]n- polyanions as templates and trz molecules as the small and delicate ligands play the decisive factors to the formation of silver chain. In addition, to improve the photocatalytic activity of the new compound Ag29SiW12, its polypyrrole (PPy) composite (PPy@Ag29SiW12) has been prepared and exhibits excellent photocatalytic activity (93.1% for MB and 48.8% for RhB) and selectivity adsorption (16.2 mg/g for MB and 1.60 mg/g for RhB) for organic dyes under the visible light radiation.

Hydrogen as a clean and environmentally friendly energy carrier has attracted extensive interest. Although Pt-based materials have been considered as the state-of-the-art catalysts for the hydrogen evolution reaction (HER), the high-cost and low-abundance hinder their practical application. Herein, we report the development of reduced graphene oxide (rGO) supported molybdenum phosphide (MoP) encapsulated in P-doped porous carbon (PC) nano-octahedrons derived from polyoxometalate-based metal–organic frameworks (POMOFs) by carbonization and subsequent phosphidation process. Impressively, combining the advantages of MoP, PC, and rGO, the composite shows superior electrocatalytic HER performance and stability, with a low onset overpotential of 62.3 mV, small Tafel slope of 53.6 mV dec–1, along with long-term durability for 10 h, which is comparable or even superior to those of the most promising MoP-based electrocatalysts in acid media reported to date. Most importantly, this work provides an elaborate strate...

Two new polyoxometalate (POM)-based three-dimensional metal organic carbene frameworks, [Ag10(trz)4(H2O)2][HPW12O40] (POMs@MCNCs-1) and [Ag10(trz)4(H2O)6][H2SiW12O40] (POMs@MCNCs-2), were hydrothermally synthesized, in which Keggin-type polyoxoanions as templates induce the formation of two different kinds of metal–carbene nanocages (MCNCs) for the first time. Combination of the reversible multielectron redox behavior and electron storage functions of POMs with the good electrical conductivity of the single-walled carbon nanotubes (SWNTs) renders the POMs@MCNCs-1/SWNT composite excellent electrochemical performance and good stability as anode materials of lithium-ion batteries, with up to 2000 mA h g–1 for the first discharge capacity and ca. 859 mA h g–1 for the second cycle at a current density of 100 mA g–1. The successful fabrication of unprecedented MCNCs into the POM-based three-dimensional metal–organic frameworks in the present work must initiate extensive research interests in diverse fields.

A new high-connected twin Keggin polyoxometalates (POM) based metal organic complex (POM@MOC), [Ag28(trz)18][HPWV3WVI9O40]2·2H2O (Ag28P2W24) (trz = 1,2,3-triazole), has been synthesized and structurally characterized. Single crystal X-ray analysis reveals that the new compound contains two unprecedented [10,10] connected Keggin POMs, which represents the highest connection number of POMs to any mixed-connected POM@MOCs to date. Another fascinating structural feature is that the twin Keggin POMs respectively dominates and fabricates two kinds of helices in the POM@MOCs. In addition, to improve the photocatalytic activity of the new compound Ag28P2W24, its polypyrrole (PPy) composite (PPy/Ag28P2W24) has been prepared and exhibits good uptake capacities and photocatalytic degradation for Rhodamine B dye under the visible light.

Controlled self-assembly of the inorganic–organic hybrid compounds based on polyoxometalates (POMs) is hampered by the wide range of oxo and hydroxo units on the peripheries of POMs and many chemic...

To overcome the flammability and smoke generation of EVA, samples with different mass fraction of magnesium hydroxide (MH) and ammonium polyphosphate (APP), have been prepared by internal mixer and...

To develop solar light-driven photocatalysts with high activity and structural stability, Ag3PO4/POM/GO heterojunction has been successfully prepared by a facile method at room temperature. Ag3PO4/POM/GO shows remarkably enhanced activity and stability for photocatalytic degradation and H2 production from water-splitting under simulated solar light. The degradation rate of Ag3PO4/POM/GO is 1.8 times and 1.2 times those of Ag3PO4 and Ag3PO4/POMs, respectively. H2 production using Ag3PO4/POM/GO is 2.0 times that of Ag3PO4/GO. The enhanced photocatalytic performance of Ag3PO4/POM/GO is attributed to the increased surface area, electronegativity and structure stability. The Z-scheme system of Ag3PO4/POM/GO effectively promotes charge separation, resulting in enhanced photocatalytic performance under simulated solar light.

Developing a convenient and accurate method for the determination of acetaminophen (APAP) content is very vital, and ferrocene (Fc) based nanocomposites coupled with polyoxometalates (POMs) as electrochemical sensor is a promising approach to address the issues. Herein, a new ternary nanocomposite of Fc based carbon nanomaterials (Fc-rGO) with PMo12 (Fc-rGO/PMo12, rGFP-n) was successfully fabricated, and the electrochemical activities and APAP detection of rGFP-n as electro-active materials were systematically investigated, and results of the differential pulse voltammetry (DPV) and electro-active surface area (0.0332 cm2) show that rGFP-1 is an excellent electrochemical sensor for APAP, and the proportion of Fc in rGFP-n can affect the charge transfer between APAP and rGFP. Under the optimal experimental conditions, rGFP-1 can be used to detect APAP with the limit of detection (LOD) of 13.27 nM (S/N = 3), the sensitivity of 36.81 μ A ⋅ μ M − 1 c m − 2 , and the detection range from 1 × 10 − 6 to 1 × 10 − 3 M , meeting the lowest plasma concentration of APAP (1.3 mM).