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The key to designing energy-efficient hydrogen production systems lies in the development of highly catalytic, low-cost non-precious metal catalysts, along with the substitution of high-energy-consuming oxygen evolution reactions with reactions involving easily oxidizable small molecules at the anode. In this paper, molybdates (NiMoO 4 and CoMoO 4) that grow on nickel foam are treated with vulcanization and nitriding methods, and Mo doped Ni 3 S 2 (Mo–Ni 3 S 2) and N doped CoMoO 4 (N–CoMoO 4) are prepared, respectively. Mo–Ni 3 S 2 exhibits excellent UOR activity requiring only 1.335 V to drive 100 mA cm−2. It is found that Mo–Ni 3 S 2 participated in both of the decomposition of urea (15.4 %) to form NH 3 and the oxidation reaction of urea (84.6 %) to form N 2 to keep the anodic reaction in the low potential range, avoiding the oxidation of nickel sites in the catalyst to form NiOOH. In addition, N–CoMoO 4 catalyst exhibits excellent hydrogen evolution reaction (HER) activity requiring only 67 mV to drive 100 mA cm−2. Finally, the catalysts prepared by molybdate are used to construct urea oxidation electrolytic system. The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) urea oxidation-assisted water splitting system requires only 1.47 V to achieve 100 mA cm−2, which is a voltage reduction of 180 mV compared to conventional water electrolysis systems. The system realizes high energy efficiency hydrogen production and urea wastewater purification. This work provides insights into the design of low-energy-consuming hydrogen production systems. [Display omitted] • The catalysts prepared by molybdate exhibit efficient UOR and HER activity. • Mo–Ni 3 S 2 follows a new UOR mechanism of urea decomposition and urea oxidation. • The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) system requires only 1.47 V to afford 100 mA cm−2. • We couple UOR and HER to construct an energy-saving hydrogen production system. [ABSTRACT FROM AUTHOR]

In this report, we have successfully prepared a series of Er3+-activated Na 0.5 La 0.5 MoO 4 green molybdate phosphors by solid-state reaction. The X-Ray diffraction patterns confirmed that all diffraction peaks of Na 0.5 La 0.5 MoO 4 :Er3+ phosphors matched well with the standard data card with orthorhombic phase and the Rietveld refinement results indicated that the space group of the crystal structure was I4 1 /a. Under 379 nm excitation, Na 0.5 La 0.5 MoO 4 :3%Er3+ phosphor exhibited strong green emission, with two strong emission peaks at 530 nm, 551 nm and a weak one centered at 656 nm, corresponding to the transitions of 2H 11/2 → 4I 15/2 , 4S 3/2 → 4I 15/2 and 4F 9/2 → 4I 15/2 , respectively. The experimental results showed that the optimal doping concentration of Er3+ was x = 3%, and electric dipole-dipole interaction was the major mechanism for the concentration quenching according to Dexter theory. Surprisingly, the optimal Na 0.5 La 0.5 MoO 4 :3%Er3+ phosphor presented thermal enhancement to the ratio of 2H 11/2 → 4I 15/2 transition to 4S 3/2 → 4I 15/2 transition in the elevated temperature range of 300–475 K. The maximum S a and S r were 1.79 × 10−2 K−1 and 1.094% K−1 respectively, which were applied to optical thermometers based on fluorescence-intensity-ratio technique. Furthermore, Na 0.5 La 0.5 MoO 4 :3%Er3+ phosphor had excellent thermal quenching performance (I 425K /I 300K = 93.47%) and high activation energy (E a = 0.366 eV). Finally, the prepared Na 0.5 La 0.5 MoO 4 :3%Er3+ green phosphor, commercial BaMgAl 10 O 17 :Eu2+ blue phosphor and CaAlSiN 3 :Eu2+ red phosphor were combined with the 365 nm near-UV chip to produce a warm white LED device with high color index (R a = 86.4) and low correlation color temperature (CCT = 4328 K). The above results suggested that the Er3+-activated Na 0.5 La 0.5 MoO 4 multifunctional phosphors had considerable potential in the field of optical temperature measurement and phosphor-converted white light emitting diodes. [ABSTRACT FROM AUTHOR]

In the last decade, mesoporous hydroxyapatite (HA) materials have received much attention regarding environmental applications (including adsorption of soil and water contaminants, films for lithium batteries, catalysts, and support systems for catalysis) and open up ample opportunities regarding biomedical devices and structures. Molybdenum ions may strongly influence catalytic and sorption properties of materials. The present study shows an influence of hydrothermal-synthesis conditions (including temperature and duration of the treatment) on phase composition, textural properties, and morphology of molybdate-containing HA. Powders with high crystallinity manifested Brunauer–Emmett–Teller specific surface area up to 55 m2/g with a pore volume of 0.33 cm3/g. The molybdate-containing HA powders were investigated by chemical analysis, X-ray diffraction, Fourier-transform IR spectroscopy, and transmission electron microscopy. Their specific surface area, pore volume, and pore size distributions were determined by low-temperature nitrogen adsorption measurements, zeta potential was quantified, and electron paramagnetic resonance spectroscopy was performed. The concentration of MoO 4 2− preserving the one-phase state was found, and the impact of hydrothermal treatment mode was analyzed by machine learning using artificial neural networks. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel low-temperature sintered ACaPr(MoO 4) 3 (A = Na, K) microwave dielectric material was prepared by the conventional solid-phase reaction method. The effects of temperatures on the crystal structure, lattice vibration characteristics, and microwave dielectric properties of the new ternary molybdate ACaPr(MoO 4) 3 (A = Na, K) ceramics were investigated. XRD and Rietveld refinement results show that ACaPr(MoO 4) 3 (A = Na, K) ceramics belong to a tetragonal scheelite structure with space group I4 1 /a. The lattice vibration mode was analyzed by Raman spectroscopy. The ACaPr(MoO 4) 3 (A = Na, K) ceramics have high density(＞95%) and excellent microwave dielectric properties with ε r = 10.78, Qf = 57726 GHz, τ f = −44.6 ppm/°C at 775 °C and ε r = 10.36, Qf = 50096 GHz, τ f = −46.2 ppm/°C at 725 °C, respectively. In addition, the excellent chemical compatibility between ACaPr(MoO 4) 3 (A = Na, K) ceramics and Ag electrodes has developed a path for its application in LTCC technology. [ABSTRACT FROM AUTHOR]

Two kinds of scheelite-structure microwave dielectric ceramics with I4 1 /a space group were prepared by the conventional solid-phase reaction method. The effects of different sintering temperatures on the crystal structure, lattice vibration and microwave dielectric properties of NaSrLn(MoO 4) 3 (Ln = Nd, Sm) ceramics were investigated. XRD and Rietveld refinement results show that NaSrLn(MoO 4) 3 (Ln = Nd, Sm) ceramics belong to tetragonal scheelite structure with I4 1 /a space group. The lattice vibration mode was analyzed by Raman spectroscopy, and the correlation between the dielectric performances and structure was established. The NaSrLn(MoO 4) 3 (Ln = Nd, Sm) ceramics have high density (>97%) and excellent microwave dielectric properties of ε r = 10.47, Qf = 38951 GHz, τ f = −48.43 ppm/°C for NaSrNd(MoO 4) 3 sintered at 775 °C and ε r = 9.55, Qf = 41081 GHz, τ f = −44.92 ppm/°C for NaSrSm(MoO 4) 3 sintered at 800 °C. In addition, NaSrLn(MoO 4) 3 (Ln = Nd, Sm) ceramics have excellent chemical compatibility with Ag electrodes, which means that the ceramic could be used in LTCC microwave devices. [ABSTRACT FROM AUTHOR]

• The effect of molybdate and vanadate as corrosion inhibitors for clad AA2024-T3 was investigated. • The inhibition degree by vanadate is linear in the concentration range from 0.5 mM to 250 mM. • The inhibition degree of molybdate is similar to vanadate for c ≤ 50 mM. • For c > 50, the inhibition effect of molybdate strongly increases shifting E br for 400 mV more positive. • The morphology and thickness of inhibitor layers on clad AA2024-T3 strongly differ for molybdate and vanadate. Molybdate and vanadate ions were used as corrosion inhibitors for the clad aluminium alloy 2024-T3 in chloride solution to investigate the differences in their inhibitory effect. Electrochemical measurements in 0.1 M NaCl investigated the influence of inhibitor concentration from 0.5 mM to 250 mM, solution pH from 5 to 9 and immersion time at open circuit potential of up to 12 h. Both compounds act predominantly as anodic inhibitors; however, the effect of molybdate increases significantly at concentrations above 50 mM and leads to a broad passive range. Surface analysis of the samples exposed to inhibitor performed by X-ray photoelectron spectroscopy showed that the inhibitor layers consist of oxides of multiple valences. Scanning electron microscopy with chemical analysis was also used to characterise the inhibitor layers. Equilibrium diagrams of the aqueous species in the selected concentration range were generated to better understand the inhibition mechanism and to correlate the electrochemical data and data on surface properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Powders of two new mixed molybdates Na 2.64 Mn 1.64 (MoO 4) 3 (1) and Na 2.62 Ni 1.69 (MoO 4) 3 (2) have been prepared via a solid-solid reaction. They are isostructural, both crystallizing in monoclinic system (S. G.: C 2/ c), Z = 1, and the unit cell parameters a = 12.74109 (18) Å, b = 13.69390 (15) Å, c = 7.20028 (8) Å, β = 112.4314 (7) °, V = 1161.22 (2) Å3 (1), and a = 12.6368 (2) Å, b = 13.3633 (2) Å, c = 7.08501 (10) Å, β = 111.9248 (10) °, V = 1109.91 (3) Å3 (2). The structure consists of a 3D network of corners and edges sharing [MoO 4 ] and [MO 6 ] polyhedral, delimiting tunnels in which the Na ions partly site. The samples were investigated by powder X-ray diffraction, infrared spectroscopy, and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDX). The vibrational study confirms the existence of the M o O 4 2 − functional groups. Laser Raman spectroscopy showed that the M o O 4 2 − tetrahedra in the two compounds are more regular, suggesting high symmetry for the compound. The as-synthesized compounds are fiber-like grains with an average length of 10−1 μm. FT-IR spectra showed the presence of all the functional groups present in the compounds. Magnetisation measurements showed their paramagnetic behaviour. The title compounds were characterized by cyclic voltammetry (CV), electrochemical performance and limiting factors are also applied as electrode material for Na-ion batteries at room temperature. Benefiting from these advantages, between 1.5 V and 4.6 V, (1) and (2) deliver high specific capacities of 230 and 160 mA h g−1 after 60 cycles, and good rate performances, respectively. It can also be inferred that the prepared electrocatalyst showed for both phases excellent Hydrogen Evolution Reaction (HER) performance with an overpotential of 531 mV for Mn and 512 mV for Ni, required to afford a current density of 10 mA cm−2. • The two compounds Na 2.64 Mn 1.64 (MoO 4) 3 (1) and Na 2.62 Ni 1.69 (MoO 4) 3 (2) are firstly reported as the Na-ion Batteries. • The two compounds 1 and 2 delivers capacity of 230 and 160 mAh.g−1 for the first cycle at 0.2C. • They displays favorable rate and stable cyclic performance as full cell. • Magnetic susceptibility measurements reveal that the two compounds are paramagnetic. [ABSTRACT FROM AUTHOR]

The uptake capacity of Mo on the active MnO 2 nanoparticles was determined in a previous study, and it was found to be 7 mg/g. This value is appropriate for 99Mo, which is more complex to separate due to its production using the 235U fission reaction with a high specific activity. Currently, multiwall carbon nanotubes (MWCNTs) linked to mesoporous MnO 2 are being prepared and studied as a novel sorbent for the 99Mo produced with a low specific activity by thermal neutron activation of natural molybdenum consisting of 92M0, 94Mo, 95Mo, 96Mo, 97Mo, 98Mo, and 100Mo, based on the 98Mo(n,γ) reaction to prepare the 99Mo/99mTc generator with a high uptake capacity for Mo. FTIR spectroscopy, EDX-mapping, XRD, particle size analysis, FESEM, and TEM analysis were used to characterize the novel mesoporous MnO 2 /MWCNT sorbent with a large total pore area 193.3 m2/g and porosity about 52%. Several factors influencing the sorption of 99Mo and 99mTc onto the mesoporous MnO 2 /MWCNTs were studied, including the distribution coefficient (K d), contact time, temperature, and sorbent/solute ratio, etc. The Mo uptake capacities on the novel sorbent were 133 and 115 mg Mo/g, respectively. A preliminary study on the prepared new sorbent for the 99Mo/99mTc generator was performed, and the elution yield of 99mTc was found to be 82.55% with low 99Mo breakthrough. The radiochemical, radionuclide, and chemical purity of the eluted 99mTc were checked to ensure that it was free of impurities. [Display omitted] • Preparation of mesoporous MnO 2 /MWCNT, which is a promising material for the 99Mo/99mTc generator with an appropriate morphological and chemical composition for low specific activity 99Mo sorption. • Comparison of the prepared composite with recently employed exchangers for the fabrication of the 99Mo/99mTc generator. • Kinetic, thermodynamic, and isotherm models were employed to study the Mo sorption process on the prepared composite. [ABSTRACT FROM AUTHOR]

Uranium-bearing radioactive wastes generated from the nuclear fuel cycle and the nuclear medicine sector require conditioning to form stable waste forms for long-term geological disposal. Various candidate ceramic and glass-ceramic composite waste forms designed for the incorporation of tetravalent uranium (U(IV)) have been developed largely based on the general observation that the oxidative dissolution of primary U(IV) minerals controls uranium migration in the geological environment. As such, waste forms must be processed under reducing conditions to maintain U(IV) and often with addition of metal powders to control the reducing environment, significantly increasing the processing cost. In addition, these U(IV) waste forms often require extensive chemical durability testing to see how U(IV) oxidation to U(VI) would impact U releases. Based on numerous natural analogue and laboratory studies, some U(VI) minerals and synthetic phases are found to be chemically durable, making them candidate U(VI) waste forms. This article is not intended to provide a comprehensive review rather serve as a perspective focusing on the current advances and future trend of the U(VI) waste forms for the encapsulation of uranium-bearing nuclear wastes, with some highlighted cases and analysis. Technical challenges and perspectives are provided to identify the knowledge gaps and opportunities for future research. Current progress on candidate hexavalent uranium waste forms has been assessed. Challenges and perspectives are given to identify the knowledge gaps for future research. [Display omitted] • Progress and status on candidate hexavalent uranium waste forms for nuclear waste management are assessed. • Current advances on uranyl silicates, titanates, zirconates, phosphates, vanadates and molybdates are briefly reviewed. • Selected uranyl minerals and synthetic phases as potential hexavalent uranium waste forms are discussed. • Technical challenges and perspectives are given to identify the knowledge gaps for potential future research. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cost-effective HER electrode was developed based on silk fabric, a sustainable resource. • The electrode offers excellent flexibility and follows a simple, environmentally friendly fabrication process. • The in situ growth of MoC 2 and the presence of carbon dots enhance the HER performance of the electrode. • The electrode exhibited robust HER activities and stability under acidic and alkaline conditions. The broad use of the electrocatalytic hydrogen evolution reaction (HER) is impeded by challenges associated with the availability and high cost of precious metal-based catalysts. Carbon materials co-doped with transition metals and nitrogen have emerged as highly promising alternatives among non-precious metal-based electrocatalysts due to their advantageous features, such as cost-effectiveness, high activity, and excellent stability. This study focuses on incorporating low-cost sodium molybdate onto silk fabric, which serves as a sustainable precursor for the preparation of nitrogen-doped carbon material. This silk fabric is then carbonized to create a flexible electrode for electrocatalytic hydrogen evolution. The resulting electrode exhibits the in situ growth of Mo 2 C and MoO 3 , and this mechanism facilitates a smoother conduction path for electrons. The resulting electrode not only possesses flexible characteristics but also exhibits a large specific surface area. Transmission electron microscopy analysis reveals the presence of carbon quantum dots, which actively contribute to the heightened catalytic hydrogen evolution activity of the prepared electrode. Experimental findings unequivocally showcase the outstanding electrocatalytic hydrogen evolution capability and operational stability of the fabricated flexible electrode in acidic and alkaline environments. This work substantiates the efficacy of using low-cost sodium molybdate-loaded silk fabric as a catalyst precursor, thereby providing robust support for the design and implementation of non-precious metal-based electrocatalysts for the HER. This approach advances the development and broader application of carbon-free fuels. [ABSTRACT FROM AUTHOR]

• Structure of alkali molybdate and tungstate glasses is probed using Raman spectroscopy. • Rheological behavior of corresponding parent supercooled liquids are reported. • Structure of glasses with ≤55 % MO 3 is dominated by isolated [MO 4 ]2− tetrahedra. • Chains of corner- and edge- sharing octahedra and tetrahedra form at higher MO 3 content. • Structural evolution is shown to be consistent with T g , viscosity and kinetic fragility. The structure of mixed-alkali (Li,Na,K) molybdate and tungstate glasses with 55-62.5 mol% MoO 3 and 53-65 mol% WO 3 is studied using Raman spectroscopy, while the rheological behavior of the corresponding supercooled liquids is measured using parallel plate rheometry. The M-O (M = Mo,W) polyhedral units in these glasses are found to be similar to those characteristic of the crystalline alkali ortho- and pyro- molybdate and tungstate phases. The structure of glasses with ≤55 % MO 3 is dominated by isolated [MO 4 ]2− tetrahedra. Increasing MO 3 content results in the formation of chain-like moieties of corner- and edge- sharing MO 6 octahedra and MO 4 tetrahedra. This compositional evolution of the glass structure is found to be consistent with the corresponding variation in T g and viscosity of the parent supercooled liquids. Moreover, the low degree of structural connectivity of these liquids is manifested in rather high kinetic fragility index that is somewhat unprecedented in archetypal oxide systems. [ABSTRACT FROM AUTHOR]

Molybdate (MoO 4) and tetrathiomolybdate (MoS 4) supplementation of rats via drinking water had opposite effects on the establishment of Nippostrongylus brasiliensis larvae but both induced hypercupraemia, temporarily inhibited activities of superoxide dismutase in liver and duodenum after infection and enlarged the femoral head. Effects of MoO 4 and MoS 4 on activities of caeruloplasmin oxidase (CpO) in plasma, erythrocyte superoxide dismutase (ESOD) and tissue copper (Cu) and molybdenum (Mo) were compared to test the hypothesis that species lacking a rumen can thiolate MoO 4. Three groups of 18 immature Wistar rats were given Mo (70 mg/L as MoO 4) or MoS 4 (5 mg/L) via drinking water or remained untreated; all received a commercial, cubed diet and 12 from each group were infected with larvae of N. brasiliensis. Rats were killed 7–9 days later and liver, kidney, spleen, heart, muscle (quadriceps), brain and bone (femur) removed for Cu and Mo analysis. Plasma Cu was greatly increased by MoO 4 and MoS 4 , without changing CpO activity, but the effect was more variable with MoO 4 and accompanied by a smaller decrease in ESOD. Tissue Cu and Mo were increased by MoS 4 in all tissues examined except brain and bone, correlating with plasma Cu and with each other; relationships were strongest in spleen, followed by kidney. MoO 4 also increased soft tissue Cu and Mo but increases were generally smaller than those induced by MoS 4 and correlations between the two elements and with plasma Cu generally weaker. Since hypercupraemia and correlated increases in liver and kidney Cu and Mo are characteristic of systemic thiomolybdate (TM) exposure, we conclude that MoO 4 was partially thiolated to give a different TM profile from that produced by MoS 4. The pathophysiological significance of systemic exposure to di- and tri-TM merits investigation in non-ruminants as agents of chelation therapy and in ruminants as agents of short-lived TM toxicity on Mo-rich pastures. Low exposure to tetrathiomolybdate (MoS 4) and moderate exposure to molybdate (MoO 4) both increase copper (Cu) concentrations in all soft tissues except brain but the extent and accompanying increase in molybdenum (Mo) vary greatly. It is hypothesized that MoO 4 is partially thiolated and the products (di- and tri-thiomolybdate) form less stable complexes with Cu than with MoS 4. [Display omitted] [ABSTRACT FROM AUTHOR]

Low molybdate (MoO 4) exposure via drinking water in mature rats infected with Nippostrongylus brasiliensis raised liver and plasma copper (Cu) concentrations. The possibility that anthelmintic effects were attributable to conversion of MoO 4 to tetrathiomolybdate (MoS 4) in a non-ruminant species was investigated by giving three groups of 18 immature rats drinking water containing 70 mg Mo l−1 as MoO 4 (group A), 5 mg Mo l−1 as MoS 4 (group B) or no supplement (group C), while receiving a commercial cubed diet. After 41 days, 12 rats from each group were inoculated subcutaneously with 2,000 L3-stage N. brasiliensis larvae. Subgroups were killed 7, 8 or 9 days post infection (dpi), when adult worms are normally expelled, and enzyme markers for the inflammatory response to infection were measured in plasma or liver. Male rats given MoS 4 prior to infection grew more slowly than those given MoO 4. Eight dpi, females given MoS 4 had lost more bodyweight than those in group C, while those given MoO 4 had gained weight. Mean worm counts at 7 dpi were 160, 65 and 250 ± 30.6 (SE), respectively, in groups C, A and B, and differed significantly from each other (P <0.05) but only rats given MoO 4 remained infected 9 dpi (mean worm count 52 ± 16.4): Faecal egg counts followed a broadly similar pattern. Both Mo sources pre-empted increases in liver and duodenal superoxide dismutase activity, induced by infection 7 and 9 dpi, respectively, in group C and enlarged the femur: neither source prevented hypertrophy of the small intestine and a rise in serum mast cell protease concentration caused by infection. Since data for plasma Cu concentration and caeruloplasmin oxidase activity, reported separately, indicated MoO 4 was thiolated in vivo , differences between Mo sources may be attributable to differences in the degree of thiolation, extent of thiomolybdate exposure and rates of thiomolybdate degradation at critical times in host or parasite development. Adding a little molybdenum (Mo) as tetrathiomolybdate (MoS 4 ; 5 mg Mo l−1) or more as molybdate (MoO 4 ; 70 mg Mo l−1) to drinking water of immature rats, infected with Nippostrongylus brasiliensis , decreased liver superoxide dismutase activity (LSOD) 7 days after infection: both sources increased femur length (FL) but had opposite effects on worm count (WC). Cellular immunity may have been compromised by MoS 4 but stimulated by MoO 4 that had been partially thiolated by sulphide generated in the large intestine. [Display omitted] [ABSTRACT FROM AUTHOR]

The single-component Na 5 Y(MoO 4) 4 :Dy3+, Tm3+ white-emitting phosphor was prepared by the sol-combustion method, and Tm3+ was codoped for color-tunable white emission. The XRD patterns confirm that the as-prepared samples have a Na 5 Y(MoO 4) 4 structure and do not change with Dy3+/Tm3+ codoping. Under ultraviolet excitation at 352 nm, the Na 5 Y(MoO 4) 4 :Dy3+ phosphor shows a characteristic white emission consisting of a weak peak at 485 nm and a strong peak at 577 nm. By codoping a small amount of Tm3+, the blue emission of phosphor is enhanced, and the chromaticity coordinates can be adjusted between (0.3663, 0.416) and (0.319, 0.3407); thus, color-tunable white emission is achieved with the synergistic effect of Dy3+ and Tm3+. The luminescence intensity of Na 5 Y(MoO 4) 4 :Dy3+, Tm3+ at 483 K still retains 72% of the initial intensity, showing excellent thermal stability. By combining Na 5 Y(MoO 4) 4 :Dy3+, Tm3+ with a 365 nm chip, the fabricated w -LED device emits bright white light for illumination. Therefore, the as-prepared Na 5 Y(MoO 4) 4 :Dy3+, Tm3+ has potential applications in the field of w -LEDs as white-emitting phosphors. [ABSTRACT FROM AUTHOR]

Molybdate (Mo+) supplements can suppress or enhance nematode infections in ruminants, depending on exposure level, but there have been no investigations in non-ruminants. Three groups of 16 mature rats were each fed a commercial diet and given Mo+ (10 mg Mo/l), tungstate (a molybdenum [Mo] antagonist) (MoO 4 , 350 mg W/l) or no supplement (C) via drinking water for 40 days before acute infection with 3,600 Nippostrongylus brasiliensis larvae. Group Mo− also received allopurinol (1 g/l), a molybdenoenzyme inhibitor, from 4 days post infection (dpi). Subgroups of four rats from each group were killed at 7–14 dpi. A group of six rats was left untreated and uninfected and subgroups killed 10 or 12 dpi. Infection reduced intakes of food and water but impacts were greatest in group Mo−. Median worm counts in groups C, Mo− and Mo+ were 900, 941 and 510, respectively, at 7 dpi and 9, 40 and 0 (P = 0.05) at 10 dpi. Median faecal egg counts were consistently lowest in group Mo+. Worm weight was reduced (P <0.05), worm tissue protease increased and superoxide dismutase activities increased in worm (P < 0.01) and host duodenal homogenates (P < 0.01) from group Mo+. In group Mo−, liver Mo concentration decreased, duodenal xanthine oxidoreductase activity (DXOR) became totally inhibited and plasma uric acid was barely detectable at 10 dpi. Plasma mast cell protease activity and duodenal malonyldialdehyde concentrations, markers of inflammation, were increased by nematode infection (P <0.001) but unaffected by water treatments. Liver Mo, liver copper (Cu) and plasma Cu concentrations were increased in group Mo+ and plasma Cu concentration was increased in group Mo− suggesting systemic exposure to partially thiolated MoO 4 and WO 4. Supplementary MoO 4 impaired larval establishment and changed parasite biochemistry without affecting the inflammatory response to infection but may have required partial thiolation to do so. Rats did not rely on DXOR activity to expel N. brasiliensis. Manipulating molybdenum status of rats affected outcome of infection with Nippostrongylus brasiliensis : raising status produced low and relatively uniform intestinal worm counts 7 days after infection, while lowering status had the opposite effect, compared with an untreated control group (C). [Display omitted] [ABSTRACT FROM AUTHOR]

Temperature-stable ULTCC composite (1- x)Li 3 AlMo 3 O 12 - x Li 0.5 Bi 0.5 MoO 4 ceramics were prepared by solid-state reaction method. X-ray and EDS results showed that Li 3 AlMo 3 O 12 phase and Li 0.5 Bi 0.5 MoO 4 phase exist independently, and no other phase is generated. Due to the low sintering temperature of both two phases, the composite ceramics can obtain high density at 560 ℃. Microwave dielectric properties mainly depend on the ceramic Li 0.5 Bi 0.5 MoO 4 content x , the addition of Li 0.5 Bi 0.5 MoO 4 effectively increases the τ f of Li 3 AlMo 3 O 12 from −65.05 ppm/℃ to 4.96 ppm/℃, but caused the dielectric loss increase. When x =0.45 and sintered at 560 ℃, microwave dielectric properties of 0.55Li 3 AlMo 3 O 12 -0.45Li 0.5 Bi 0.5 MoO 4 ceramics with close zero τ f : ε r = 15.32, Q × f = 13,158 GHz, τ f = 4.96 ppm/℃. • The composite ceramics can obtain high density at 560 ℃. • Exhibits excellent chemical compatibility with metallic aluminum. • The τ f value was adjusted to near-zero successfully (τ f = 4.96 ppm/°C). • Optimum microwave dielectric properties (ε r = 15.32, Q× f = 13158 GHz and τ f = 4.96 ppm/°C) were achieved. [ABSTRACT FROM AUTHOR]

Thiolation can convert molybdate (MoO 4) into a series of thiomolybdates (MoS x O 4-x) in the rumen, terminating in tetrathiomolybdate (MoS 4), a potent antagonist of copper absorption and, if absorbed, donor of reactive sulphide in tissues. Systemic exposure to MoS 4 increases trichloroacetic acid-insoluble copper (TCAI Cu) concentrations in the plasma of ruminants and induction of TCAI Cu in rats given MoO 4 in drinking water would support the hypothesis that rats, like ruminants, can thiolate MoO 4. Data on TCAI Cu are presented from two experiments involving MoO 4 supplementation that had broader objectives. In experiment 1, plasma Cu concentrations (P Cu) tripled in female rats infected with Nippostrongylus brasiliensis after only 5 days exposure to drinking water containing 70 mg Mo L−1, due largely to an increase in TCAI Cu; activities of erythrocyte superoxide dismutase and plasma caeruloplasmin oxidase (CpOA) were unaffected. Exposure for 45–51 days did not raise P Cu further but TCA-soluble (TCAS) Cu concentrations increased temporarily 5 days post infection (dpi) and weakened the linear relationship between CpOA and TCAS Cu. In experiment 2, infected rats were given less MoO 4 (10 mg Mo L−1), with or without iron (Fe, 300 mg L−1), for 67 days and killed 7 or 9 dpi. P Cu was again tripled by MoO 4 but co-supplementation with Fe reduced TCAI Cu from 65 ± 8.9 to 36 ± 3.8 μmol L–l. Alone, Fe and MoO 4 each reduced TCAS Cu in females and males when values were higher (7 and 9 dpi, respectively). Thiolation probably occurred in the large intestine but was inhibited by precipitation of sulphide as ferrous sulphide. Fe alone may have inhibited caeruloplasmin synthesis during the acute phase response to infection, which impacts thiomolybdate metabolism. [Display omitted] [ABSTRACT FROM AUTHOR]

To improve the luminescence property of Sm3+ in Y 2 Mo 3 O 12 , partial Ca2+-F- co-substituted Y 2 Mo 3 O 12 :Sm3+ phosphor, namely Y 2- x Ca x Mo 3 O 12- x F x :Sm3+, was prepared using a solid-state method. The effect of introducing Ca2+-F- ion pairs on structure and luminescence properties of Y 2 Mo 3 O 12 :Sm3+ was studied in depth. XRD patterns not only manifested that all as-prepared Y 2- x Ca x Mo 3 O 12- x F x :Sm3+ samples had standard Y 2 Mo 3 O 12 structure, but also indicated the introduction of Ca2+-F- ion pairs did not cause the change of crystal structure. Under the near ultraviolet excitation of 404 nm, the emission peaks of Y 2 Mo 3 O 12 :Sm3+ were located at 567 nm, 605 nm and 652 nm, respectively, resulting from the 4f→4f electron transitions of Sm3+ ions. Furthermore, the luminescence intensity of Sm3+ was obviously enhanced through the co-substitution of Y3+-O2- ions with Ca2+-F- ions in Y 2 Mo 3 O 12 structure, and the chromaticity coordinates moved towards red region, which due to the environmental effect of crystal field around Sm3+. Besides, the red LED device was manufactured for suitable chromaticity parameters. All results indicated that the as-prepared Y 1.84 Ca 0.06 Mo 3 O 11.94 F 0.06 :0.10Sm3+ red-emitting phosphor could become a promising candidate for application of white light-emitting diodes and plant illumination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dithiol-assisted molybdate or tungstate based film were fabricated on copper. • The fabricated films exhibited double-layer structure. • The top layer was organic layer and underlayer consisted of Cu 2 S. • The oxidation of dithiol by molybdate or tungstate resulted in a thicker film. • The films exhibited high corrosion protection efficiency. An approach to fabricate protective film on copper substrate utilizing molybdate or tungstate assisted by dithiol was proposed. The fabricated films exhibited double-layer structure. The top layer was an organic layer primarily composed of interconnected dithiol molecules through disulfide bonds originating from the oxidation of molybdate or tungstate. The Cu 2 S bottom-layer formed as a result of the cleavage of C-S bonds subsequent to the adsorption of dithiol molecules onto the copper matrix. The molybdate participated the film via MoO x and MoS x. Although no tungstate species were detected in the film, the oxidizing effect of tungstate facilitated a conversion of dithiol molecules into polymers, resulting in a significantly thicker surface layer. The corrosion protection efficiencies of the films reached 99.7 % and 99.8 %, respectively, attributed to the incorporation of molybdate or tungstate additives. Theoretical calculations provided valuable insights into the process of film formation and elucidated the relationship between film structure and anti-corrosion performance. [ABSTRACT FROM AUTHOR]

A series of Na 5 Y(MoO 4) 4- y A y :Dy3+ (A = WO 4 2−, VO 4 3−; y = 0–0.05) phosphors were synthesized by the combustion method. Some of the MoO 4 2− sites were occupied by WO 4 2− and VO 4 3− anions, which enhanced the luminescence property of Dy3+-doped Na 5 Y(MoO 4) 4. XRD results show that the crystal structures of the samples were consistent with the standard Na 5 Y(MoO 4) 4 phase. Under excitation at 352 nm, the Na 5 Y(MoO 4) 4- y A y :Dy3+ phosphors exhibited a characteristic blue emission at 485 nm and a yellow emission at 577 nm, which originated from the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 transitions of Dy3+ ions, respectively. White light can be achieved by combining these blue and yellow emissions. After replacing MoO 4 2− with WO 4 2− and VO 4 3− anions in Na 5 Y(MoO 4) 4 :Dy3+, the luminescence intensity of Dy3+ was significantly improved due to the crystal field effect. The results indicate that Na 5 Y(MoO 4) 3. 97 (WO 4) 0.03 :Dy3+ and Na 5 Y(MoO 4) 3. 97 (VO 4) 0.03 :Dy3+ phosphors have good prospects for application in n-UV-excited w-LEDs. [ABSTRACT FROM AUTHOR]

Eu3+ activated red phosphors based on the CaY x (MoO 4) 1.5x+1 (x = 0.2, 0.4, 0.6, 1, 2) as host materials were synthesized by using a combustion method. XRD analysis demonstrated that the synthesized samples matched with the standard card CaMoO 4 (JCPDS NO.77-2239) belonging to the tetragonal of the I4 1 /a space group. All samples showed several narrow sharp emission peaks under 393 nm n-UV excitation, the strongest of which was at 618 nm attributed to the 5D 0 →7F 2 transition of Eu3+. The optimal composition of the host was found to be CaY 0.6 (MoO 4) 1.9 (hereafter referred to as CYMO). After doping Sm3+ into CYMO:Eu3+ phosphor, the absorption peaks of Eu3+ at 393 and 464 nm were broadened, and the peak intensity was also significantly higher than that of single-doped Eu3+. The energy transfer phenomenon between Sm3+ and Eu3+ was discovered by the excitation and emission spectra in CYMO:Eu3+,Sm3+ phosphors, and verified by the fluorescence lifetime of Sm3+ ions in the phosphors. The energy transfer mechanism between Sm3+ and Eu3+ is a dipole-dipole interaction, where the energy transfer efficiency in CYMO phosphor doped with 13% Eu3+ and 3% Sm3+ is 17.9%. The CIE coordinate and color purity were calculated as (x = 0.6598, y = 0.3388) and 93.72%, which indicated that the CYMO:13%Eu3+,3%Sm3+ phosphor is a red phosphor with excellent performance for potential application in n-UV light excited w-LEDs. [ABSTRACT FROM AUTHOR]

• MoSe 2 -CoSe 2 /CoAl-LDH was synthesized by one-step hydrothermal method. • The introduction of MoSe 2 -CoSe 2 can improve the conductivity of CoAl-LDH. • The catalytic activity of Co2+ in CoAl-LDH is enhanced by in situ selenylation. • The electrocatalyst can be produced at low cost and on a large scale by this work. For many advanced energy technologies, it is essential to produce non-precious metals, high activity, and low charge transfer resistance electrocatalysts through low cost and simple methods. In this work, MoSe 2 -CoSe 2 @CoAl-LDH composite was synthesized by a one-step hydrothermal method. Compare with the CoAl-LDH catalyst, the prepared MoSe 2 -CoSe 2 @CoAl-LDH composite exhibits an excellent OER performance with a low overpotential (320 mV at 10 mA·cm−2), a small Tafel slope (71 mV·dec−1). The prominent OER performance of the MoSe 2 -CoSe 2 @CoAl-LDH composite can be mainly attributed to the fast electron transfer from the CoAl-LDH to MoSe 2 -CoSe 2 and the catalytic activity promoted by the energy change of Co2+ due to the introduction of Se, which can be confirmed by EIS and XPS results, respectively. The strategy of this work may provide a low-cost and facile way for large-scale synthesis of non-precious metal modified hydrotalcite composite. Compared with CoAl-LDH, the prepared MoSe 2 -CoSe 2 @CoAl-LDH composites exhibits an excellent OER performance with a low overpotential of 320 mV at 10 mA ·cm−2, a small Tafel slope of 71 mV·dec−1. The outstanding OER performance of the MoSe 2 -CoSe 2 @CoAl-LDH composites is mainly attributed to the surperior conductivity of MoSe 2 -CoSe 2 and the catalytic activity promoted by the binding energy change of Co2+ due to the introduction of Se. [Display omitted] [ABSTRACT FROM AUTHOR]

Knowledge of the identity and thermodynamic properties of aqueous molybdenum (Mo) species at elevated temperatures and pressures is important for understanding the extraction of Mo from source rocks and the formation of hydrothermal deposits. Chlorine and sulfur are two major components in crustal fluids. Several studies have investigated Mo speciation and solubility in chloride-bearing hydrothermal fluids, but little is known about the behaviour of Mo in sulfur-bearing systems. We used in-situ synchrotron X-ray absorption spectroscopy (XAS) measurements and molecular dynamics (MD) simulations to investigate the predominant Mo species in S-bearing (0.04–2 m NaHS) solutions at 30–394 °C (XAS) and 77–300 °C (MD) and 800 bar. The XAS data show that, similar to previous room temperature studies, the S2− ion progressively replaces O2− in molybdate (MoO 4 2−) to form thiomolybdates (MoO 4- x S x 2−, x = 1, 2, 3, 4) with increasing NaHS concentrations at temperature up to 394 °C. The MD simulations confirm the identity and structure of the thiomolybdate species determined from the XAS experimental data. The speciation calculations based on the formation constants for the thiomolybdate species extrapolated from the room temperature data agree well with the experimental results. This study indicates that thiomolybdate species are likely to be important in transporting Mo in sulfur-bearing hydrothermal fluids with wide pH ranges (e.g., pH 5–9 at 300 °C) under reduced (sulfide stable) conditions in the Earth crust. Current models of Mo transport in hydrothermal ore fluids need to be re-evaluated to take into account the thiomolybdate species. [ABSTRACT FROM AUTHOR]

Novel gel polymer electrolyte (hydrogel) was prepared by incorporation of poly (vinylphosphonic acid) (PVPA) as a host matrix and redox active ammonium molybdate, Mo. Supercapacitors including active carbon electrodes were fabricated using hydrogels, PVPA/MoX where X represents the percent fraction of Mo in PVPA. All the electrolytes were in gel form and show excellent bending and stretching properties in a device. The electrochemical performance of the devices was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) experiments. Surprisingly, the specific capacitance (Cs) of the device increased to 1276 F g−1 which is at least 50 times enhancement by introducing Mo as mediator compared to the PVPA based system. The supercapacitor with PVPA/Mo10 has the highest energy density of 180.2 Wh kg−1 at a power density of 500 W kg−1. The device with the same hydrogel structure exhibited higher performance after 2300 charge-discharge cycles and the maintained 85% of its initial capacitance performance. A supercapacitor was fabricated using PVPA/Mo10 and tested under bent and twisted conditions confirming remarkable capacitance retention. Image 1 • A novel hydrogel poly (vinylphosphonic acid) + ammonium molybdate was produced. • The specific capacitance of the device was improved up to 1276 F g−1. • The energy density of 180.2 Wh kg−1 at a power density of 500 W kg−1 was reached. • Supercapacitor retained its performance under bent and twisted conditions. [ABSTRACT FROM AUTHOR]

Y 2- x (MoO 4) 3- y (BO 3) y : x Sm3+ and Y 2- x (MoO 4) 3- y (PO 4) y : x Sm3+ orange-red phosphors were synthesized using a conventional solid-state reaction. The effects of Sm3+ doping concentration and substitution by anion groups BO 3 3− and PO 4 3− on the crystal structure and luminescent performance were studied in detail. XRD results indicated that all samples had a standard Y 2 (MoO 4) 3 structure with space group Pbcn, and BO 3 3− and PO 4 3− entered the lattice without initiating an impurity phase. At an excitation of 404 nm, the Y 2- x (MoO 4) 3 : x Sm3+ orange-red phosphors exhibited three narrow-band emissions at 567 nm, 605 nm, and 652 nm, due to transitions of 4G 5/2 → 6H 5/2 , 4G 5/2 → 6H 7/2 and 4G 5/2 → 6H 9/2 of Sm3+, respectively. In addition, substitution of MoO 4 2− by BO 3 3− and PO 4 3− resulted in significant improvement of the luminescence of the Y 2 (MoO 4) 3- y (BO 3) y :Sm3+ and Y 2 (MoO 4) 3- y (PO 4) y :Sm3+ phosphors compared to Y 2 (MoO 4) 3 :Sm3+ phosphors, especially in terms of luminescent intensity. The results indicated that Y 1.9 (MoO 4) 2.97 (BO 3) 0.03 :0.1Sm3+ and Y 1.9 (MoO 4) 2.94 (PO 4) 0.06 :0.1Sm3+ orange-red phosphors, having excellent luminescence, are promising orange-red components for warm white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Several new iron molybdates have been synthesized under hydrothermal conditions at relatively low temperatures (200 °C) to stabilize the Fe3+ oxidation state. The mineralizers are all sodium ion based and three new phases were isolated as high quality single crystals from various reaction stoichiometries, Fe(MoO 4)(OH) (I), Na 0·15 Fe 2 Mo 3 O 12 (H 2 O)·0.25H 2 O (IIa), and NaFe(MoO 4) 2 (H 2 O) (III). The structures contain iron oxide octahedra arranged in chains (I), dimers (IIa), and isolated octahedra (III), that are linked by various molybdate oxyanions to form 3-D framework (I), 3-D framework with channels (IIa), and 2-D sheets in their iron molybdate motifs. Both I and III are lightly colored materials containing valence precise Fe3+, whereas IIa contains partially occupied Na + ions in columns within the lattice leading to concomitant valence mixing of Fe2+/Fe3+ with a corresponding darker color to the crystal. If sodium ions are not included in the synthesis and instead replaced by smaller Li + ions in the reaction, there is no alkali metal incorporation in the lattice and the resultant compound Fe 2 Mo 3 O 12 (H 2 O)·0.25H 2 O (IIb) is formed. This is isostructural to IIa but without the partially occupied Na + ions in the channels which makes it another valence precise Fe3+ compound that is nearly colorless as expected since all transtions are spin forbidden in the high spin Fe3+ case. The role of carbonate as a mineralizer was examined since the reaction is highly acidic (pH ∼ 1) in the absence of carbonate, and this does not lead to satisfactory product formation. The carbonate mineralizer increases the pH to 6–6.5, and this pH is maintained throughout the reaction, which does lead to high quality crystal products. Despite its absence in any of the products, the carbonate mineralizer plays an additional important (albeit unknown) role in the synthesis, because if simple hydroxide is used to increase the pH to 6–6.5, the resultant products are much lower in quality and yield. [Display omitted] • Single crystals of Fe(MoO 4)OH, Na 0·15 Fe 2 Mo 3 O 12 (H 2 O)·0.25H 2 O, Fe 2 Mo 3 O 12 (H 2 O)·0.25H 2 O, and NaFe(MoO 4) 2 (H 2 O) were grown hydrothermally. • Phase formation depended on reaction stoichiometry and the presence of sodium. • A carbonate buffer mineralizer facilitates the formation of these ferric molybdates. • The structures exhibit differing iron oxide motifs, which are variously bridged by molybdate groups. • Elemental analysis and vibrational spectroscopy support the structure assignments. [ABSTRACT FROM AUTHOR]

This study successfully grew KBaY(MoO 4) 3 crystals doped with single Er3+ ions and co-doped with Ca2+/Er3+ ions using the top-seeded solution growth method. Thermal analysis of the KBaY(MoO 4) 3 crystals was performed by differential scanning calorimetry, and their phase and structure were characterized using X-ray diffraction and Fourier transform infrared spectroscopy. The luminescent properties of the crystals in the visible and near-infrared wavelength ranges under different concentrations of Er3+ ions were analyzed through emission spectroscopy, and the concentration quenching mechanism was investigated in depth. The results showed that the strongest emission intensity was obtained at an Er3+ ion concentration of 5 mol%. Additionally, by substituting Ba2+ ions with Ca2+ ions, the emission intensity was significantly enhanced, especially when the Ca2+ ion doping concentration reached 6 mol%, resulting in the maximum emission intensity. Furthermore, we investigated the effects of matrix structure and lattice distortion on the spectral properties by employing Judd-Ofelt (J-O) theory and studying energy transfer mechanisms. The mechanisms of Ca2+-induced fluorescence quenching and factors influencing the fluorescence decay time were analyzed. Through the analysis of the absorption cross-section, emission cross-section, and gain cross-section of crystals with different Ca2+ ion concentrations, it was found that Ca2+, Er3+: KBYM crystals exhibited a low laser pump threshold. The results demonstrate that the 6 mol% Ca2+, 5 mol% Er3+: KBYM crystals possess excellent performance and are a promising laser gain medium. • A series of Er3+: KBYM and Ca2+, Er3+: KBaY(MoO 4) 3 crystals were successfully grown using the top seeded solution growth method. • The optimum doping concentration of Er3+ ions in KBaY(MoO 4) 3 crystal was investigated, and the energy transfer mechanism and fluorescence quenching mechanism of Er3+ ions were described in detail. • The doping of Ca2+ ions will reduce the symmetry of the local environment around Er3+ ions. • After doping with Ca2+ ions, the visible and near-infrared range emission intensity of Ca2+, Er3+: KBaY(MoO 4) 3 crystals has been greatly improved. • The absorption, emission and gain cross sections of Ca2+ doped crystals with different concentrations were calculated, and the potential of Ca2+, Er3+: KBYM crystals for laser output was evaluated. [ABSTRACT FROM AUTHOR]

Molybdenum is an essential trace element for humans but can be harmful with excess assimilations or chronic exposures. In this study a polymer-functionalized nanocomposite (HFO-PsAX) was fabricated for selective adsorption of molybdate from aqueous solution. HFO-PsAX was prepared by grafting hydrous ferric oxide nanoparticles (HFOs) into the porous structure of a polystyrene anion exchanger (PsAX) by in situ synthesis method. The resultant HFO-PsAX exhibited greatly enhanced selectivity toward molybdate as compared with the matrix, PsAX, which is also a fair adsorbent for scavenging molybdate. The competitive abilities of the ubiquitous anions, i.e., chloride, carbonate, sulfate, and phosphate, on the adsorption of molybdate by HFO-PsAX followed the order: chloride < phosphate < carbonate < sulfate. The unexpectedly weak competitive ability of trivalent phosphate may be due to incompletely dissociated state and formation of molybdate-phosphate complexes. The optimal pH for the adsorption of molybdate was determined as pH ≈ 4, which is associated with the dissociation constants of molybdic acid; certain adsorption capacities were also observed even under extremely alkaline condition (pH = 14) for single-component molybdate solution. Temperature (10, 25, and 40 °C) has negligible effect on the adsorption capacities by HFO-PsAX, and Freundlich model and Dubinin-Radushkevich (D-R), Temkin model can describe the adsorption isotherms well. The adsorption potential of Temkin model is calculated as ≈100 J/mol, which is between those of physisorption and chemisorption process. Fixed-bed column adsorption experiments validated the potential of HFO-PsAX in treating Mo(VI) contaminated water for practical application, and the exhausted HFO-PsAX can be regenerated by a binary NaOH-NaCl solution (both 5% in mass) without loss in adsorption capacities. Unlabelled Image • Enhanced adsorption selectivity of Mo(VI) by HFO-PsAX was achieved. • The competitive effect of phosphate is weaker than those of carbonate and sulfate. • Maximum Mo(VI) adsorption capacities of HFO-PsAX occurred at pH around 4. • Temperature almost has no influence on Mo(VI) adsorption by HFO-PsAX. • Mo(VI)-saturated HFO-PsAX can be regenerated by NaOH-NaCl solution (both 5% in mass). [ABSTRACT FROM AUTHOR]

The objective of this work was to synthesize nanocomposites based on cationic polyelectrolytes and silver nanoparticles using poly(N-vinylbenzyl-N-triethylammonium chloride) as polymer phase. For that, a nanostructured crosslinker was synthesized from silver nanoparticles (AgNPs) and acrylic acid. Molybdate retention properties of nanocomposites were studied in function of pH and ionic strength. In addition, their antimicrobial properties were evaluated against E. coli and S. aureus. It was evidenced that AgNPs can be stabilized using acrylic acid and that this material can be incorporated to the polymer phase during polymerization by free radical of cationic monomers. The effect of pH on retention of molybdate, by the nanostructured polymer, was significant only to low ionic strength (the order seen was pH 5.0 > pH 7.0 > pH 9.0 for 0.0% NaCl). Results suggest that the main interaction influencing the molybdate retention is electrostatic in nature. Finally, antimicrobial activity was enhanced by incorporation of polymerizable nanostructured crosslinker based on AgNPs. [ABSTRACT FROM AUTHOR]

A series of trivalent samarium doped lanthanum molybdate nanophosphors were prepared by co-precipitation route. The formation of highly crystalline tetragonal nanocrystals with space group I41/a is identified from powder X-ray diffractogram. The morphology and the oriented attachment mediated growth mechanism of the nanocrystals were recognized from TEM analysis. The strong and broad charge transfer band in the near ultra violet region favours excellent excitation of the nanophosphors and the energy transfer from host matrix to Sm3+ ions is established on account of the characteristic emissions of trivalent samarium ions upon host sensitization. The Judd-Ofelt (JO) theoretical analysis was carried out to have an insight into the spectroscopic characteristics of La 2-x Sm x (MoO 4) 3 nanophosphors. The relatively higher value of Ω 2 predicts more asymmetric environment of Sm3+ sites in the host lattice, favouring the dominance of electric dipole transitions and the various radiative parameters are evaluated. In spite of the excitation channel, the 4G 5/2 → 6H 9/2 transition of Sm3+ observed at 645 nm is the most prominent emission transition. The maximum emission intensity is observed for La 1.98 Sm 0.02 (MoO 4) 3 nanophosphors and as the doping concentration exceeds this limit, there will be fall in emission intensity due to concentration quenching effect. A detailed investigation on the decay behaviour of host sensitized and direct excited emission of samarium ions was conducted and the average lifetime values are calculated. The CIE chromaticity co-ordinates calculated for different excitation routes fall in the reddish orange region of CIE diagram and the same for La 1.98 Sm 0.02 (MoO 4) 3 nanophosphors are found to be (0.601, 0.394) with a colour purity of 97.21% which disclosed the relevance of La 2−x Sm x (MoO 4) 3 as a potential red phosphor material. Image 1 [ABSTRACT FROM AUTHOR]

A series of Eu3+ doped NaSrLa(MO 4) 3 (M = Mo and W) stable red-emitting phosphors were synthesized and their structural properties were analyzed systematically. Rietveld refinement analysis of the phosphors confirms that all the phosphors crystallizing in a tetragonal phase with space group I 4 1 / a. In addition, in order to understand more about the structural parameters, Raman spectra for the NaSrLa(MoO 4) 3 , NaSrLa(WO 4) 3 and Eu substituted lattices were executed. The optical properties of all the phosphors were shown intense red emission (electric dipole (ED) transition). Temperature-dependent PL measurements exposed that NaSrLa 0.2 Eu 0.8 (MoO 4) 3 retains 66.13% of PL efficiency at 150 °C. The absolute quantum yield of the selected (NaSrLa 0.2 Eu 0.8 (MoO 4) 3 and NaSrEu(WO 4) 3) phosphors show 83% and 64.9% under excitation at 394 nm, respectively. The red LEDs were fabricated for the selected phosphors with the near UV LED chip (395 nm) operated at 20 mA forward bias. The results indicate that the synthesized phosphors can act as a promising red phosphor for use in near UV-pumped white LEDs. Image 1 • Eu3+ doped NaSrLa(MO 4) 3 (M = Mo and W) stable red-emitting phosphors were synthesized by the solid-state method. • The synthesized phosphor is 8.6 times higher than the commercial Y 2 O 3 :Eu3+ red phosphor. • The absolute quantum yield of the phosphor is 83%. • The red phosphor shows excellent thermal stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Tailoring Co/CoMoO4 interface is achieved by hydrogenation treatment of core@shell cobalt carbonate hydroxide@CoMoO4. • Core@shell Co@CoMoO4 nanowires exhibit superior HER performance, quite closing to that of commercial PtC in 1.0 M KOH. • Synergistic effect between Co and CoMoO4 is responsible for the magnificent activity enhancement. Abstract Tailoring efficient and stable electrocatalysts based on non-noble metal elements for hydrogen evolution reaction (HER) is highly imperative for the commercialization of water splitting electrolysors. Herein, a self-standing core@shell Co@CoMoO 4 nanowire array (Co@CoMoO 4 NA) electrode is developed by calcination of a cobalt carbonate hydroxide@CoMoO 4 (CCH NA@CoMoO 4) precursor under H 2 /N 2 atmosphere. In this way, synergistic Co/CoMoO 4 heterostructure interfaces and 3D porous electrode architecture are built up, which are proved to be reliable strategies for HER catalytic activity enhancement. In 1.0 M KOH solution, Co@CoMoO 4 NA electrode exhibits an impressive activity with an extremely low overpotential of 46 mV at 10 mA cm−2, quite closing to that of commercial PtC (31 mV at 10 mA cm−2). These findings may inspire the exploration of new electro-catalysts for efficient HER by modulating multiple components interfaces. [ABSTRACT FROM AUTHOR]

Abstract We prepared CaMoO 4 : x%Sm3+, 5%Tb3+ (x = 0.1, 0.5, 1, 2) phosphors by a precipitation method. Based on the diversity in thermal quenching behavior of different ions in molybdate, a novel thermometry strategy has been proposed. The fluorescence intensity ratio (FIR) of Sm3+ to Tb3+ in these composites exhibits remarkable temperature dependence due to the diverse thermal quenching behaviors of Sm3+ and Tb3+ ions. Excellent temperature sensitivity was achieved from 293 K to 593 K, suggesting that these can perform thermometry. The sensitivities increase with Sm3+ concentration. The maximum sensitivity is as high as 0.312 K−1 (at 593 K) when the Sm3+ concentration is 2%. However, the low Sm3+ concentration sample has a greater relative sensitivity; the maximum value is as high as 0.019 K−1 (at 460 K) when the Sm3+ concentration is 0.1%. Lower Sm3+ concentrations suggested a greater range of luminescent color changes with temperature. Thus, the sample with less Sm3+ can measure temperature via luminescent color. Graphical abstract We prepared CaMoO 4 : Sm3+, Tb3+ phosphors by a precipitation method. The fluorescence intensity ratio (FIR) of Sm3+ to Tb3+ in these composites exhibits remarkable temperature dependence due to the diverse thermal quenching behaviors of Sm3+ and Tb3+ ions. Experimental results show that the temperature sensitivity and relative sensitivities of samples are higher. In addition, the luminescent color of phosphors turns from green to orange red with the temperature increases. The change of luminous color is very ocular. In summary, the Sm3+ and Tb3+ co-doped CaMoO 4 phosphors have potential applications in temperature sensing material. Unlabelled Image Highlights • The CaMoO 4 : Tb3+, Sm3+ prepared by a simple and low cost method of precipitation. • The FIR of Sm3+ and Tb3+ is obviously changed with temperature change. • The sample has a high temperature sensing sensitivity and relative sensitivity. • The luminescent color change of the sample is obviously with temperature change. [ABSTRACT FROM AUTHOR]

Abstract Rhenium and molybdenum are valuable metals present in the earth's crust in very low concentration and are increasingly used in industry thanks to their multiple properties, but due to the harmful aspects of the production process, there is a need to develop systems of concentration or purification of salts of these elements. For this work a PEG/Na 2 MoO 4 aqueous two phase system (ATPS) was used for the partition of ReO 4 - anion. By using a central composite design, the effects of PEG concentration, sodium molybdate concentration, temperature, pH and their possible interaction on the partition coefficient were studied, also to estimate the optimal configuration of the factors that influence the process. At the same time, experimental density, sound velocity and isentropic compressibility were also obtained for top and bottom phases. The results showed that the optimal conditions for the partition of ReO 4 − anion using the ATPS formed by PEG and Na 2 MoO 4 were 14.7 wt% PEG 4000, 16.3 wt% Na 2 MoO 4 , 35 °C and pH 6. For these conditions, the partition coefficient (K) obtained was up to 17.8 ± 0.78. The order of factors with high significance on the partition coefficient was: Na 2 MoO 4 concentration > PEG concentration > temperature > pH > interaction between Na 2 MoO 4 and PEG concentrations; the effect of these parameters mainly is related with the speciation, salting-out effect and hydrophobicity. The influence of these factors on the density, and sound velocity of the top phase was minimal, unlike its influence on the properties of the bottom phase, not isentropic compressibility and effect of PEG and Na 2 MoO 4 concentrations on sound velocity. The evaluation of the partitioning behavior was made by experimental design, applying statistical regression analysis and analysis of variance (ANOVA). The statistical models for partition coefficient and for phase densities (and the other properties) as function of parameters with significant effects were obtained, and also a good correlation between experimental and correlated data was observed (R-Squared = 0.9379, ReO 4 − partition coefficient; 0.9882, bottom phase; and 0.9836 upper phase). This work is oriented to the possible application in stripping of a top phase provided for a co-extraction of rhenium and molybdenum by ATPS in acidic media or in solutions with high contend of Mo such as those provided by pressure oxidative leaching of molybdenite in basic media. Highlights • The Na 2 MoO 4 + PEG 4000 + H 2 O system was used for the ReO 4 − anion partitioning (K). • Central composite design was used to evaluate effects of factors on responses. • The factors considered: pH, temperature and concentrations of PEG 4000 and Na 2 MoO 4. • Salting-out effect of molybdenum anions was analyzed according to its speciation. • Best configuration: 14.7 wt% PEG 4000, 16.3 wt% Na 2 MoO 4 , 35 °C and pH 6; K = 17.8. [ABSTRACT FROM AUTHOR]

Abstract For the corrosion protection of steel rebars in concrete, five different molybdate-phosphate conversion coatings were prepared, by changing the molybdate-phosphate ratio in the conversion baths. Their composition and morphology were studied with GD-OES, XPS, Raman spectroscopy and SEM-EDX and a schematic representation of their structure is suggested. Further, the corrosion resistance properties of the coatings were evaluated in a simulated concrete pore solution (CPS) containing chlorides, using anodic polarization measurements. Thanks to the elaborated surface analysis their corrosion behaviour could be correlated to their structure. The results show that by altering the molybdate-phosphate ratio the structure and, consequently, the corrosion protection properties change significantly. By optimizing this ratio a twofold protection mechanism could be attained, demonstrating both good barrier properties and consistent with active corrosion protection. Graphical Abstract Highlights • Five different molybdate-phosphate conversion coatings were prepared by varying the concentration of molybdate and phosphate in the conversion bath • Elaborated surface analysis study to explain electrochemical behaviour • By fine-tuning the molybdate/phosphate balance, one can achieve two-fold protection mechanism: a physical barrier combined with active corrosion protection [ABSTRACT FROM AUTHOR]

Highlights • An OECD TG-416 two-generation reproductive study of Mo as sodium molybdate dihydrate. • Rats given 0, 5, 17, or 40 mg Mo/kg/day in drinking water or 40 mg Mo/kg/day in diet. • Assessed estrus cycle, sperm, mating, fertility, litter size, pup survival & growth. • No adverse effect on reproductive function at any dose level in either generation. • NOAELs: 17 & 40 mg Mo/kg/day for systemic & reproductive toxicity respectively. Abstract In an OECD Test Guideline 416 multigenerational study, groups of 24 male and 24 female Sprague-Dawley rats were administered sodium molybdate dihydrate at 0, 5, 17, or 40 mg molybdenum (Mo)/kg bw/day in the drinking water or 40 mg Mo/kg bw/day in the diet over two generations to assess reproductive toxicity. No adverse effect on reproductive function was observed at any dose level in either generation as indicated by no significant dose-related effect on estrus cycles, sperm parameters, mating, fertility, gestation, litter size, pup survival, growth or postnatal development. Systemic toxicity, including decreased body weight, food consumption (males only) and water consumption, was observed among both sexes given 40 mg Mo/kg bw/day in the diet. Serum levels of Mo and copper were increased in a dose-related manner. The No Observed Adverse Effect Levels (NOAEL) are 17 mg Mo/kg bw/day for systemic toxicity and 40 mg Mo/kg bw/day for reproductive toxicity. [ABSTRACT FROM AUTHOR]

Abstract Bi 2 MoO 6 had been studied as a photocatalyst, ferroelectric, anti-bacterial, microwave dielectric, etc. No significant studies on the luminescence in Bi 2 MoO 6 had been previously reported. In this work, NIR emission of Nd3+ activator sensitized by Bi 2 MoO 6 host is reported. The excitation is in form of a broad band covering entire nUV-blue region of the spectrum. NIR emission around 1 µm and the broad band excitation is highly suitable for several applications like modification of solar spectrum for solar photovoltaics. Apart from Nd3+ emission, NIR emission around 979 nm resulting from Nd3+→ Yb3+ energy transfer is also reported. Mechanisms of host → Nd3+ and Nd3+→ Yb3+ energy transfer are suggested. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Abstract An anaerobic incubation was launched with varying nitrate (1, 5, 10 and 20 mM exogenous NaNO 3) and molybdate (20 mM Na 2 MoO 4 , a sulfate-reducing inhibitor) additions to investigate the characteristics of PCP dechlorination, as well as the reduction of natural co-occurring electron acceptors, including NO 3 −, Fe(III) and SO 4 2−, and the responses of microbial community structures under a unique reductive mangrove soil. Regardless of exogenous addition, nitrate was rapidly eliminated in the first 12 days. The reduction process of Fe(III) was inhibited, while that of SO 4 2− reduction depended on addition concentration as compared to the control. PCP was mainly degraded from orth -position, forming the only intermediate 2,3,4,5-TeCP by anaerobic microbes, with the highest PCP removal rate of average 21.9% achieved in 1 and 5 mM NaNO 3 as well as 20 mM Na 2 MoO 4 treatments and the lowest of 7.5% in 20 mM NaNO 3 treatment. The effects of nitrate on PCP dechlorination depended on addition concentration, while molybdate promoted PCP attenuation significantly. Analyses of the Illumina sequencing data and the relative abundance of dominant microorganisms indicated that the core functional groups regulated PCP removal at genera level likely included Bacillus , Pesudomonas, Dethiobacter , Desulfoporosinus and Desulfovbrio in the nitrate treatments; while that was likely Sedimentibacter and Geosporobacter_Thermotalea in the molybdate treatment. Nitrate supplement but not over supplement, or addition of molybdate are suggested as alternative strategies for better remediation in the nitrate-deficient and sulfur-accumulated soil ecosystem contaminated by PCP, through regulating the growth of core functional groups and thereby coordinating the interaction between dechlorination and its coupled soil redox processes due to shifts of more available electrons to dechlorination. Our results broadened the knowledge regarding microbial PCP degradation and their interactions with natural soil redox processes under anaerobic soil ecosystems. Graphical abstract Image 1 Highlights • Effects of N and Fe/S status on PCP removal was studied in a flooded mangrove soil. • Moderate not over supply of NO 3 − and SO 4 2--reducing suppression facilitated PCP removal. • Various mechanisms operated in facilitated PCP removal. • Synergistic microbes but not typical dechlorinators mediated the facilitated PCP removal. • Coordinating electron transfer of microbial respiration improved PCP remediation. Coordinating electron transfer of microbial respiration improved PCP remediation through moderate not over supply of NO 3 − and SO 4 2--reducing suppression. [ABSTRACT FROM AUTHOR]

Abstract A series of Cr 2-x Sc x (MoO 4) 3 solid solutions with tunable monoclinic-to-orthorhombic phase transition temperature have been synthesized via solid-state reaction. X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results show that all synthesized Cr 2-x Sc x (MoO 4) 3 (0 < x ≤ 1.4) solid solutions are single phased with no impurities identified, which reveals that Cr3+ has been substituted by Sc3+ in Cr 2 (MoO 4) 3. Monoclinic to orthorhombic phase transition temperature of Cr 2-x Sc x (MoO 4) 3 can be effectively tuned from 372 °C to room temperature as the substituted Sc3+-content (x) varies from 0 to 1.4. The synthesized Cr 0.6 Sc 1.4 (MoO 4) 3 crystalizes in an orthorhombic structure at room temperature, exhibiting anisotropic negative thermal expansion throughout the testing temperature range. The coefficient of thermal expansion measured by thermal mechanical analyzer (TMA) for Cr 0.6 Sc 1.4 (MoO 4) 3 is −11.17 × 10−6 °C−1 in the testing temperature range of 30–600 °C. Moreover, the crystallization, micromorphology, density and coefficient of thermal expansion of Cr 0.6 Sc 1.4 (MoO 4) 3 are obviously sensitive to the twice sintering temperature, whereas none of such sensitivity is found for the phase transition temperature. [ABSTRACT FROM AUTHOR]

A molybdate-incorporated cooperative catalyst CuMo-BPY was synthesized and explored in the highly efficient and atom-economical assisted tandem process for conversion of CO 2 and olefins into value-added cyclic carbonates. [Display omitted] • A molybdenum(VI) oxide incorporated cooperative catalyst, CuMo-BPY , was achieved by a simple and effective way. • The spatial matching of duple catalytic sites provide further compatibility and drive the tandem catalytic proceeded. • CuMo-BPY was explored in the atom-economical assisted tandem process to synthesize cyclic carbonates from olefins and CO 2. • CuMo-BPY has advantages of unambiguous structure, economic chemical reagents and highly stability. • CuMo-BPY will be promising for preparation of practical chemical materials. Currently, substantial interest is focused on developing assisted tandem catalysis to optimize the reaction conditions for each step in the process. By combining a molybdate oxidation catalyst and alkaline μ 3 -OH tricopper (II) cores into a metal-organic framework (MOF), a bifunctional catalyst, Cu 3 (μ 3 -OH) 2 (4,4′-BPY)(MoO 4) 2 (CuMo-BPY , BPY = 4,4′-bipyridine), was achieved and successfully explored for the assisted tandem catalytic conversion of olefins into value-added cyclic carbonates. CuMo-BPY displayed a three-dimensional (3D) extended network of two-dimensional (2D) inorganic CuMo layers interconnected with 4,4′-bipyridine groups. Two potential catalytic sites, Mo(VI) oxide (an oxidant for the epoxidation of olefins) and the alkaline μ 3 -OH of tricopper (II) cores (for the capture and activation of CO 2), exhibit an orderly distribution and spatial matching in the framework, which can provide further compatibility with the Mo=Ot-activated epoxidation intermediate to drive tandem catalysis in a single workup stage. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo), a redox-sensitive trace metal, plays an important role in recording ancient oxygenation and deoxygenation events as a paleoredox proxy. The mobility and reactivity of Mo in aqueous conditions are closely tied to the chemistry of reduced sulfur and iron species. However, our current knowledge on the formation, structure, stability, and condensation pathways of FeMoS clusters in aqueous settings remains limited, which has driven the current study. In this study, we conducted systematic experiments investigating the interactions between dissolved Mo (initially introduced as molybdate, MoO 4 2−, or tetrathiomolybdate, MoS 4 2−), ferrous iron (Fe2+), and sulfide (ΣH 2 S aq) in variously defined abiotic sulfidic systems to determine the external conditions (i.e., pH, and reactant concentrations and ratios) necessary for the formation of solid-phase Fe-Mo sulfides. Solution samples of each system were monitored using ultraviolet-visible spectroscopy (UV–vis) to track the degree of thiolation of dissolved Mo species. Precipitates were analyzed using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) to determine their elemental compositions and valences, and structure (i.e., crystalline or amorphous), respectively. All FeMoS precipitates were amorphous and contained 76–90% Mo(IV) and 10–24% Mo(V) with a trend toward lower Mo(IV):Mo(V) ratios with increasing pH. The degree of Mo thiolation, which was strongly dependent on solution pH and Fe2+ concentrations, greatly affected the amount of Mo sequestered (i.e., an increased degree of Mo thiolation in solution led to an increased amount of Mo in the final FeMoS precipitate). These findings suggest that changes in pH and Fe2+ concentrations may be responsible for the sulfide-independent variations in Mo behavior observed in euxinic basins. [ABSTRACT FROM AUTHOR]

A new series of red luminescent K 5 La(MoO 4) 4 : x Eu3+ (KLMO: x Eu3+) phosphors (x = 0.05–1.00 mol) was successfully synthesized by a high-temperature solid phase reaction at a low reaction temperature (600 ℃). The X-ray diffraction (XRD) pattern, photoluminescence properties, thermal quenching mechanism, quantum efficiency, and lifetime decay curves of the phosphors were measured and discussed in detail. The prepared phosphors exhibited strong red-light emission (at 615 nm) upon excitation at 394 nm, attributed to the electric dipole 5D 0 -7F 2 transition of Eu3+. The optimal doping concentration of phosphors is 0.8 mol. The quenching temperature of the KLMO:0.80Eu3+ phosphor was found to exceed 480 K, with high activation energy (E a) of 0.43 eV, showing good thermal stability. Impressively, the KLMO:0.80Eu3+ phosphor with a 0.8 mol concentration of Eu3+ doping also has an internal quantum efficiency (IQE) of up to 84.5%. The packaged white light emitting diode (w-LED) showed a good color rendering index (CRI) (89), correlated color temperature (CCT) (5117 K), and the Commission International de L′Eclairage (CIE) chromaticity coordinates (0.342, 0.345). Furthermore, the KLMO:0.80Eu3+ phosphor was surface-functionalized with oleic acid (OA) (KLMO:0.80Eu3+@OA) to help better identify Level I-III fingerprint details with high resolution and contrast. The results show that the KLMO:Eu3+ and KLMO:Eu3+@OA phosphors have very promising applications in the w-LEDs and latent fingerprints (LFPs). • Novel K 5 La(MoO 4) 4 :Eu3+ phosphors have been synthesized via solid-phase method. • The K 5 La(MoO 4) 4 :Eu3+ phosphor has good thermal stability and a high internal quantum efficiency of 84.5%. • The w-LED fabricated by the phosphor exhibits high-performance. • The surface-functioned phosphor shows great potential in LFP and lip print visualization. [ABSTRACT FROM AUTHOR]

Catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone with H 2 O 2 was performed at a mild temperature of 40 °C and atmospheric pressure, using ZnAl (ZA) or MgAl (MA) layered double hydroxides (LDHs) modified with tungstate and molybdate anions as catalysts in heterogeneous medium. The catalysts were prepared by direct anion exchange reactions of tungstate and molybdate on LDHs intercalated with chloride/carbonate anions. All the solids showed catalytic activity in the cyclohexane oxidation, with slight selectivity for the ketone product. The catalytic efficiency was sensitive to the M2+ present in the composition of the LDH as well as to the anions. ZnAl-modified with WO 4 2- was more active and more selective for ketone than the MgAl-modified WO 4 2- or any molybdate-based LDH catalysts. [Display omitted] • Layered double hydroxides decorated with tungstate and molybdate anions. • Catalysts based on LDHs for oxidation of cyclohexane with H 2 O 2 under mild conditions. • Tungstate and molybdate anions as catalysts for oxidation reaction. • Solid catalysts for cyclohexane oxidation with slight selectivity for the ketone product. [ABSTRACT FROM AUTHOR]

Groups of 24 weanling female Sprague-Dawley rats were administered molybdenum (Mo) as sodium molybdate dihydrate (SMD) in drinking water at target dose levels of 0, 20, or 40 mg Mo/kg bw/day and fed a semi-purified marginal copper (6.2 ppm Cu) AIN-93 G diet for 8 weeks prior to mating, through cohabitation and pregnancy until Gestation Day 21. The objective was to confirm the reproductive and developmental effects of SMD reported by Fungwe et al. (1990) at estimated doses as low as 1.5 mg Mo/kg bw/day in a similarly designed study with marginal Cu diet (6.3 ppm). There were no test material-related effects at 20 or 40 mg Mo/kg bw/day on mortality, clinical observations, body weight, body weight gain, food consumption, estrous cycling, reproductive performance, maternal macroscopic pathology, ovarian or uterine parameters, litter size, resorptions, fetal sex ratio, fetal weight, or external fetal malformations or variations. Water consumption was increased compared to controls at both dose levels during the pre-mating and gestation periods, with no apparent adverse impact. There was no evidence of copper depletion in serum at any dose level. In conclusion, the no-observed-adverse-effect levels (NOAELs) for systemic, maternal reproductive, and developmental toxicity in this marginal Cu diet study are 40 mg Mo/kg bw/day, consistent with the results of guideline developmental and reproductive toxicity studies of SMD. The results of Fungwe et al. were not replicated, even at higher dose levels of Mo, and their inconsistencies with guideline toxicity studies of Mo are not explained by the marginal dietary Cu level. • Developmental toxicity study of molybdenum in rats fed marginal copper diet (6.2 ppm). • Results comparable to guideline-compliant studies in rats with adequate Cu diet. • NOAEL is 40 mg Mo/kg bw/day with either marginal or adequate Cu diets. • No evidence of copper depletion in serum found at any dose level of Mo. • Previous findings of Fungwe et al. (1990) were not confirmed. [ABSTRACT FROM AUTHOR]

A new series of Li 3 Ba 2 La 3(1-x) Y 3x (MoO 4 ) 8 microwave dielectric ceramics were prepared by a conventional solid-state reaction method. The Rietveld refinement results further confirm that Li 3 Ba 2 La 3(1-x) Y 3x (MoO 4 ) 8 belongs to a monoclinic system with space group C2/c. Scanning electron microscopy results reveal that Li 3 Ba 2 La 3(1-x) Y 3x (MoO 4 ) 8 ceramics can be well sintered at a low sintering temperature. In addition, the permittivity (ε r ) of Li 3 Ba 2 La 3(1-x) Y 3x (MoO 4 ) 8 ceramics was found to decrease gradually with increasing substitution content of Y 3+ , while the quality factor (Qxf) and temperature coefficient of resonant frequency (τ f ) increase with x monotonously. The x = 0.4 ceramic sintered at 700 °C for 4 h possesses optimum microwave dielectric properties of ε r ∼ 14.4, Qxf ∼ 14,994 GHz (at 9.0 GHz) and τ f ∼ + 6.9 ppm/°C. Particularly, no chemical reaction between the matrix phase and Ag metal suggests that the Li 3 Ba 2 La 1.8 Y 1.2 (MoO 4 ) 8 ceramic might be a promising candidate for low-temperature co-fired ceramic applications. [ABSTRACT FROM AUTHOR]

Abstract Transition metal and rare earth (RE) elements are important fission products present in used nuclear fuel, which in high concentrations tend to precipitate crystalline phases in vitreous nuclear waste forms. Two phases of particular interest are powellite (CaMoO 4) and oxyapatite (Ca 2 RE 8 (SiO 4) 6 O 2). The glass compositional dependencies controlling crystallization of these phases on cooling from the melt are poorly understood. In the present study, the effect of rare earth identity and modifier cation field strength on powellite and apatite crystallization were studied in a model MoO 3 -containing alkali/alkaline-earth aluminoborosilicate glass with focus on (1) influence of rare earth cation size (for RE3+: Ce, La, Nd, Sm, Er, Yb) and (2) influence of non-framework cations (RE3+, Mo6+, Na+, Ca2+). Quenched glasses and glass-ceramics (obtained by slow cooling) were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray absorption spectroscopy (XAS), and electron probe microanalysis (EPMA). All samples were X-ray amorphous upon quenching, except the Ce-containing composition which crystallized ceria (CeO 2), and the sample devoid of any rare earth cations which crystallized powellite. On heat treatment, powellite and oxyapatite crystallized in the majority of the samples, with the former crystallizing in the volume and the latter on the surface. The EPMA results confirmed a small concentration of boron in the oxyapatite crystal structure. RE cations were incorporated in the glass, as well as in powellite, oxyapatite, and in the case of Yb3+, keiviite (Yb 2 Si 2 O 7). Raman spectroscopy showed that the primary vibration band for molybdate MoO 4 2− in the glasses was strongly affected by the ionic field strength of the modifying cations (alkali, alkaline earth, and RE), suggesting their proximity to the MoO 4 2− ions in the glass, though the Mo O bond length and coordination according to XAS suggested little local change. Highlights • Powellite forms on slow cooling when Mo present and incorporates rare earth. • Oxyapatite (Ca,RE) 10-x (Si,B) 6+x O 26 forms with all rare earths tested with sizes from La to Yb. • Yb favors keiviite Yb 2 Si 2 O 7 with minor oxyapatite. • Oxyapatite does not form when Na is removed from formulation. • Cations with larger field strength strongly affect molybdate oxyanion vibrations. [ABSTRACT FROM AUTHOR]

Two novel heterometallic compounds, namely, {[Cu(5,5′-Me 2 bpy) 2 ] 2 MoO 4 }(NO 3 ) 2 ·3H 2 O ( 1 ) and [Cu(phen) 2 Mo 2 O 7 (phen)]·{[Cu(phen) 2 ] 2 MoO 4 }(NO 3 ) 2 ·15H 2 O ( 2 ), where phen = 1,10-henantroline, 5,5′-Me 2 bpy = 5,5′-dimethyl-2,2′-bipyridine, have been isolated under mild conditions. The influence of the copper source and organic ligands on the products composition has been investigated. Both compounds were characterized by elemental, TG/DTA and single crystal X-ray diffraction analyses, IR and EPR spectroscopies. [ABSTRACT FROM AUTHOR]

CaMoO 4 : 5% Tb 3+ , x% Eu 3+ (x = 0.3, 0.5, 1, 2) phosphors were synthesized successfully via precipitation method. The Temperature-dependent photoluminescence (PL) spectra of the synthesized phosphors were measured. Fluorescence Intensity Ratio (FIR) of Eu 3+ to Tb 3+ is dependent on temperature, and the FIR increases with the increase of temperature. The Fluorescence Intensity Ratio was used characterize the temperature. When FIR of Eu 3+ to Tb 3+ is used to characterize the temperature, the sensitivity increases with the increase of Eu 3+ concentration. The maximum value of sensitivity is 0.095 K −1 (at 603 K), when the concentration of Eu 3+ is 2%. The sensitivity is one order of magnitude higher than common Er 3+ activated materials. In addition, the lower concentration of Eu 3+ , the greater change range of luminescent color of the samples which is reflected from color coordinates. [ABSTRACT FROM AUTHOR]

The uniform monodisperse rectangular-like rare-earth-activated CaGd 2 (MoO 4 ) 4 :Ln 3+ (Ln = Eu 3+ , Tb 3+ , Dy 3+ and Sm 3+ ) phosphors have been synthesized by conventional solid state reaction method. The prepared phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and photoluminescence (PL) spectroscopy measurements. The XRD and FTIR results showed a scheelite-type tetragonal structure for the prepared powder samples. FTIR spectra exhibited a high absorption band situated at around 846 cm −1 , which was ascribed to the Mo–O antisymmetric stretching vibrations into the [MoO 4 ] 2- tetrahedron groups and the SEM image reveals particle size in the range of 120–160 nm. The excitation/emission spectra and life times were measured to characterize the luminescent properties of the phosphors. All properties show that CaGd 2 (MoO 4 ) 4 :Ln 3+ (Ln = Eu 3+ , Tb 3+ ,Dy 3+ and Sm 3+ ) compounds are a very appropriate red, green, yellow and orange-red emitting light–emitting phosphors promising for lighting applications. [ABSTRACT FROM AUTHOR]

The susceptibility of Zn-based materials to corrosion in an aggressive environment limits their broad applications. Innovative conversion treatment is the most interesting approach for enhanced corrosion performance of zinc. This review covers recent research that has led to advances in conversion coating technology for zinc; including the application of contemporary methods for chemical conversion coating, the establishment of a corrosion protection framework for zinc, the illumination of processing control effects, and the attempts at the inhibition mechanisms of zinc by coatings. This review drawing from many sources provides an impartial focus on new achievements. The environmentally acceptable conversion coating is reviewed in detail. This review also covers engineering application aspects, including cost-effectiveness technology and process productivity. Finally, future prospects and present challenges in the field of conversion treatment are reviewed, identifying the demerit of each technique, meanwhile attempting to also identify future developments and directions. [ABSTRACT FROM AUTHOR]