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In this work, a series of Mo-containing polyoxometalates (POMs) modified separators to inhibit the growth of lithium dendrites, and thus improving the lifespan and safety of the cells is proposed. When the deposited lithium forms dendrites and touches the separator, the optimized Dawson-type POM of (NH 4 ) 6 [P 2 Mo 18 O 62 ]·11H 2 O (P 2 Mo 18 ) with the stronger oxidizability, acts like a "killer", is more inclined to oxidize Li 0 into Li + , thus weakening the lethality of lithium dendrites. The above process is accompanied by the formation of Li x [P 2 Mo 18 O 62 ] (x = 6-10) in its reduced state. Converting to the stripping process, the reduced state Li x [P 2 Mo 18 O 62 ] (x = 6-10) can be reoxidized to P 2 Mo 18 , which achieves the reusability of P 2 Mo 18 functional material. Meanwhile, lithium ions are released into the cell system to participate in the subsequent electrochemical cycles, thus the undesired lithium dendrites are converted into usable lithium ions to prevent the generation of "dead lithium". As a result, the Li//Li symmetrical cell with P 2 Mo 18 modified separator delivers exceptional cyclic stability for over 1000 h at 3 mA cm -2 and 5 mAh cm -2 , and the assembled Li-S full cell maintains superior reversible capacity of 600 mAh g -1 after 200 cycles at 2 C., (© 2023 Wiley-VCH GmbH.)

The use of WO3 as an acid catalyst has received extensive attention in recent years. However, the correlation between the catalytic activity and the predominantly exposed surface with varied acidic sites needs further understanding. Herein, the effects of the Brønsted and Lewis acid sites of different crystal facets of WO3 on the catalytic conversion of furfuryl alcohol (FA) to ethyl levulinate (EL) in ethanol were investigated in detail. A yield of EL up to 93.3% over WO3 with the (110) facet exposed was achieved at 170 °C, while FA was mainly converted to polymers over (001) faceted nanosheets and nanobelts with exposed (002) and (100) facets. This was attributed to the different distribution of the acidic sites on different exposed crystal facets. The (110) faceted WO3 possessed abundant and strong Brønsted acid sites, which favored the conversion of FA to EL, while the (100) faceted WO3 with stronger Lewis acid sites and weaker Brønsted acid sites mainly led to the formation of polymers. In addition, the (110) faceted WO3 showed excellent sustainability in comparison with the (100) faceted counterpart.

Peroxidase nanoenzymes exhibit a specific affinity toward substrates, thereby demonstrating application potential for realizing the colorimetric immunoassays of hydrogen peroxide (H 2 O 2 ), which can be further used as a probe for imaging cancer cells. To enhance the intrinsic peroxidase activity of molybdenum sulfide (MoS 2 ) nanomaterials, gold (Au) nanoparticles with an average diameter of approximately 2.1 nm were modified on a MoS 2 /carbon surface (denoted as MoS 2 /C-Au 600 ) via ascorbic acid reduction. MoS 2 /C-Au 600 can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to generate a blue oxidation product in the presence of H 2 O 2 ; this product exhibits peroxidase-like activities, superior to those of most existing MoS 2 -based nanoenzymes. Furthermore, MoS 2 /C-Au 600 exhibits a high detection capability for H 2 O 2 in the range of 1 × 10 -5 to 2 × 10 -4 mol/L (R 2  = 0.99), and the lowest detection limit is 1.82 µmol/L in a sodium acetate and acetic acid buffer solution. Steady state kinetics studies indicate that the catalytic mechanism is consistent with the ping-pong mechanism. Given its strong absorption peak at 652 nm in the visible region, MoS 2 /C-Au 600 can be used to image cancer cells due to the enhanced permeability and retention effect. Our findings demonstrate that the synergistic electronic coupling between multiple components can enhance the peroxidase activity, which can facilitate the development of an effective, facile, and reliable method to perform colorimetric immunoassays of H 2 O 2 and cancer cells., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

On the basis of maintaining the original characteristics of each component, the composite material obtains the properties that the single component does not have through the synergy between the components. It is of great significance to understand the synergy between the components for the development of the composite. First of all, we prepared different emitting CdTe quantum dots (QDs), and then fabricated CdTe QDs@reduced graphene oxide (rGO) composites by a simple ultrasonic method. It is found that the fluorescence of QDs quenched, the photocurrent significantly improved, but the growth rate different from each other because of the different QDs. Afterwards, on the basis of naked QDs, hybrid SiO₂-coated QDs were fabricated by a two-step method. After that, hybrid SiO₂-coated CdTe QDs@rGO composites were prepared by the same method. It is found that the existence of the hybrid SiO₂ shell leads to the decrease of photocurrent of the composites before and after coating, but the specific capacitance significantly improved, and the cycle stability also better than the naked QDs. This research will make grapheme-based composites have broad application prospects in energy storage equipment.

WO 3-x was deposited on TiO 2 (B) nanosheets prepared using TiCl 4 to form layered heterostructures via a two-step solvothermal synthesis, in which the horizontal growth of WO 3-x on TiO 2 (B) nanosheets was carried out using WCl 6 and ascorbic acid as a reducer. Optimized preparation conditions allowed WO 3-x /TiO 2 (B) layered heterostructures to be formed. The photo- and electro-chemical properties of layered heterostructures depended strongly on the amount of WO 3-x . The WO 3-x /TiO 2 (B) heterostructures demonstrated perfect catalytic performance in full solar-spectrum light and a fast degradation effect for dye and organic colorless pollutant. All target chemicals were degraded within 10 min using WO 3-x /TiO 2 (B) samples as a photo-catalyst in the full solar-spectrum. The photo-assisted production kinetic of Cr(VI) ions were tested. The results indicate that the reproduction rate of Cr(VI) ions using WO 3-x /TiO 2 (B) sample is three times higher than the initial TiO 2 nanosheets. The result of the photo current and Mott-Shottky curve indicates that enhanced catalysis activity is ascribed to the surface of the metastable TiO 2 (B) with Ti 3+ defects and oxygen vacancies as active sites for photocatalytic reaction. In addition, the loading of WO 3-x greatly broadened the light absorption range of TiO 2 (B), meaning that the product responded in the full solar spectrum.

An in situ electrochemical method was used to assess the cytotoxicity of chlorophenols using human breast cancer (MCF-7) and cervical carcinoma (HeLa) cells as models. On treatment with different chlorophenols, the electrochemical responses of the selected cells, resulting from the oxidation of guanine and xanthine in the cytoplasm, indicated the cell viability. In addition, the in situ in vitro electrochemical method was further compared with the traditional MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. Although similar cytotoxicity data were obtained from both methods, the effective concentrations of chlorophenols that inhibited 50% cell growth (EC50 values) from the electrochemical method were only slightly lower than those from the MTT assay. These results indicate that the in situ in vitro electrochemical method paves a simple, rapid, strongly responsive, and label-free way to the cytotoxicity assessment of different chlorophenol pollutants., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Two electrochemical signals ascribed to xanthine/guanine and hypanthine/adenine in MCF-7 cells were detected at 0.726 and 1.053 V, respectively. Based on the intensity of signals, the genistein-induced proliferation and suppression of MCF-7 cells could be evaluated. The results showed that with the increase of genistein dose at the range of 10(-9) to 10(-6)M, the two electrochemical signals of MCF-7 cell suspension increased due to the proliferation, whereas the tendency at the high dosage range of more than 10(-5)M was decreased. The proliferation and cytotoxicity obtained by the electrochemical method were in agreement with those obtained by cell counting and the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium] method. Thus, the two-signal electrochemical method is an effective way to evaluate the effect of drugs on cell activity based on purine metabolism., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Keggin-type heteropolyanion H(3)PMo(12)O(40) encapsulated by a cationic surfactant dioctadecyldimethylammonium chloride (DODACl) has been assembled on ITO substrates using an electrophoretic approach. The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), IR spectra, X-ray photoelectron spectra (XPS) and cyclic voltammetry. The AFM images exhibit a spherical assembly of surfactant-encapsulated complex (SEC) nanoparticles with uniform size. The SEM was also used to investigate the surface topography. It is the first report that the thin films of SEC are fabricated using this method, which provides a new route to explore the possibility of application to polyoxometalate-based hybrid inorganic-organic materials.

Multilayer films of tungstophosphate anion (P(2)W(18)) and poly(allylamine hydrochloride) (PAH) were fabricated on quartz and ITO substrates by layer-by-layer self-assembly method. These films were characterized by UV-vis spectroscopy, cyclic voltammetry (CV), chronoamperometric (CA), chronocoulometry (CC) and atomic force microscopy (AFM). The effects of film structure on multilayer electrochromic properties were investigated. The electrochromic responses of the composite films were related to the surface coverage of anion and multilayer thickness. It was found that higher concentration of polycation and anion, or adding salt to the polycation solution used for multilayer film preparation led to thicker and denser film structure which improved optical contrast and coloration efficiency whereas prolonged response time.

Two inorganic polyoxoanions react with carbon dioxide in aqueous solution to yield two polymeric chainlike complexes, where an activated CO2 molecule covalently bonds to polyoxoanions in a linear mu-eta1,eta1-OCO style. For the first time, the CO2 coordination is realized by an economic and environmentally friendly approach.

An interesting eight-connected self-catenated metal-organic framework, based on bimetallic {Cu4V4O12} clusters as nodes, defines a new self-catenated topology for eight-connected networks and represents the first self-catenated framework using heterometallic clusters as nodes.

The first O,O'-bonded metal-stabilized sulfinate has been isolated and structurally characterized to show a novel one-dimensional chain structure containing both the enantiomers of the subunit Mn(2-sinic)(DMSO)2.

Electrochromic multilayer films consisting of polyoxometalate (POM) cluster alpha-K(10)[P(2)W(17)O(61)].17H(2)O (P(2)W(17)), copper(II) complex [Cu(II)(phen)(2)](NO(3))(2) (phen = 1,10-phenithroline), and iron complex [Fe(II)(phen)(3)](ClO(4))(2) were fabricated on silicon, quartz and ITO substrates by layer-by-layer self-assembly method. The multilayer films, PSS/Cu(II)(phen)(2)/[(P(2)W(17)/Cu(II)(phen)(2))](n) and PSS/Fe(II)(phen)(3)/[(P(2)W(17)/Fe(II) (phen)(3))](n) were characterized by UV-vis spectra, X-ray photoelectron spectra, cyclic voltammetry (CV), chronoamperometric (CA) and in-situ spectral electrochemical measurements. The interesting feature of the electrochromic film is its adjustable color by reduction of both transition metal complex and polyoxometalate at different potentials. The multilayer films also exhibit high optical contrast, suitable response time and low operation potential due to the presence of mono-lacunary-substituted polyoxometalate and transition metal complex. This is the first example that the color of electrochromic film can be adjustable, which gives valuable information for exploring new electrochromic materials with tunable colors.