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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]

A series of Tb3+-activated NaLa(MoO4)2 phosphates were synthesized by solid-state reaction at 800 ℃ for 5 h. Comprehensive characterization of these samples included X-ray diffraction characteristics, luminescence spectra, scanning electron microscopy and analysis of luminescence decay curves. The luminescence analysis indicated that the strongest emissions occurred at wavelengths of 544 nm, 591 nm, and 615 nm. The colour of the fluorescence emission can change from red-orange to red and then to yellow-green light depending on the cvaoncentration ratio of Eu3+ and Tb3+ under different excitations. The CIE chromaticity coordinates demonstrated variability across different color ranges, showcasing the phosphor's capacity for color tuning. The energy yield was 94% when Eu3+ was 0.3 in direct comparison.The versatility in color tuning and high energy efficiency of this bis-molybdate phosphor make it a promising candidate for diverse applications in color display technologies and illumination. [ABSTRACT FROM AUTHOR]

A Molybdate intercalated copper–aluminium hydrotalcite (CAM) material was synthesised using a simple co-precipitation technique, employing varying amounts of molybdate anions. Powder XRD, FT-IR, and TEM studies revealed the presence of molybdate species in the interlayer spaces and the formation of layered hydrotalcite structures. The resultant CAM materials have been explored for the hydrogenation of 5-hydroxymethyl furan using water as a green solvent in liquid-phase conditions under a hydrogen atmosphere. The catalyst showed around 60% conversion with the selective formation of 2,5-bishydroxymethyl furan (BHMF). The activity remains intact for five cycles. The increase in reaction temperature enhanced the conversion level to 80%, with the cost of a decrease in the selectivity of BHMF to 74%. The uniform dispersion of copper-molybdenum and strong interaction in the presence of a hydrogen atmosphere favoured better activity. [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]

As a fission product in high‐level radioactive nuclear waste, Mo has low solubility in borosilicate glass. Fe2O3 is not only a prevalent transition metal element but also a major corrosion product in high‐level radioactive nuclear waste. Against this backdrop, the effect of Fe2O3 content on the structure and chemical durability of typical molybdenum‐containing sodium borosilicate glasses for nuclear waste immobilization are studied. The results show that the samples containing more than 3.85 mol% Fe2O3, a completely homogenous amorphous glass sample is obtained. Moreover, the mechanism of the effect of Fe2O3 on the solubility of Mo is discussed in detail. In this work, a portion of Fe3+ is reduced to Fe2+ and enters into the glasses as a charge compensation ion as Fe2+O6. Concurrently, Fe3+ ions contribute to the formation of the glass networks as Fe3+O4. Iron incorporation can improve the chemical durability of the sample. [ABSTRACT FROM AUTHOR]

In nature, methylmercury (MeHg) is primarily generated through microbial metabolism, and the ability of bacteria to methylate Hg(II) depends on both bacterial properties and environmental factors. It is widely known that, as a metabolic analog, molybdate can inhibit the sulfate reduction process and affect the growth and methylation of sulfate-reducing bacteria (SRB). However, after it enters the cell, molybdate can be involved in various intracellular metabolic pathways as a molybdenum cofactor; whether fluctuations in its concentration affect the growth and methylation of aerobic mercury methylating strains remains unknown. To address this gap, aerobic γ-Proteobacteria strains Raoultella terrigena TGRB3 (B3) and Pseudomonas putida TGRB4 (B4), as well as an obligate anaerobic δ-Proteobacteria strain of the SRB Desulfomicrobium escambiense CGMCC 1.3481 (DE), were used as experimental strains. The growth and methylation ability of each strain were analyzed under conditions of 500 ng⋅L-1 Hg(II), 0 and 21% of oxygen, and 0, 0.25, 0.50, and 1 mM of MoO4. In addition, in order to explore the metabolic specificity of aerobic strains, transcriptomic data of the facultative mercury-methylated strain B3 were further analyzed in an aerobic mercuric environment. The results indicated that: (a) molybdate significantly inhibited the growth of DE, while B3 and B4 exhibited normal growth. (b) Under anaerobic conditions, in DE, the MeHg content decreased significantly with increasing molybdate concentration, while in B3, MeHg production was unaffected. Furthermore, under aerobic conditions, the MeHg productions of B3 and B4 were not influenced by the molybdate concentration. (c) The transcriptomic analysis showed several genes that were annotated as members of the molybdenum oxidoreductase family of B3 and that exhibited significant differential expression. These findings suggest that the differential expression of molybdenum-binding proteins might be related to their involvement in energy metabolism pathways that utilize nitrate and dimethyl sulfoxide as electron acceptors. Aerobic bacteria, such as B3 and B4, might possess distinct Hg(II) biotransformation pathways from anaerobic SRB, rendering their growth and biomethylation abilities unaffected by molybdate. [ABSTRACT FROM AUTHOR]2-. In addition, in order to explore the metabolic specificity of aerobic strains, transcriptomic data of the facultative mercury-methylated strain B3 were further analyzed in an aerobic mercuric environment. The results indicated that: (a) molybdate significantly inhibited the growth of DE, while B3 and B4 exhibited normal growth. (b) Under anaerobic conditions, in DE, the MeHg content decreased significantly with increasing molybdate concentration, while in B3, MeHg production was unaffected. Furthermore, under aerobic conditions, the MeHg productions of B3 and B4 were not influenced by the molybdate concentration. (c) The transcriptomic analysis showed several genes that were annotated as members of the molybdenum oxidoreductase family of B3 and that exhibited significant differential expression. These findings suggest that the differential expression of molybdenum-binding proteins might be related to their involvement in energy metabolism pathways that utilize nitrate and dimethyl sulfoxide as electron acceptors. Aerobic bacteria, such as B3 and B4, might possess distinct Hg(II) biotransformation pathways from anaerobic SRB, rendering their growth and biomethylation abilities unaffected by molybdate. [ABSTRACT FROM AUTHOR]

THIS study aimed to get a simple and reliable method to enhance the shelf life of compost tea. Freshly prepared compost tea was dispensed into transparent 1.5 L plastic bottles, enabling visual monitoring, with each bottle containing 1.3 L of compost tea. The treatments included T1 (3 mM sodium nitrate), T2 (6 mM sodium nitrate), T3 (0.2 mM sodium molybdate), T4 (0.4 mM sodium molybdate), and T5 (control without additives). The experiment was conducted in triplicate, and the bottles were stored in darkness at room temperature. Samples were withdrawn from each bottle at intervals of 2, 5, 10, 15, 25, and 30 days for analysis. At the end of the storage period, compost tea preparations underwent FT-IR analysis, revealing critical molecular features. A controlled pot experiment was conducted to evaluate the in vivo efficacy of the stored compost tea by assessing its impact on the growth and developmental progress of Corchorus Olitorius plants. Additionally, the enumeration of distinct microbial communities within the rhizosphere of the growing plants was performed. After 30 days, the most effective treatments compared to the control (T5) were T2 with increased bacterial Colony Forming Unit (CFU) (7.21) and Total Fungal colony (4.23), while T1 and T2 showed higher Azotobacter counts (4.95 and 5.00) respectively. However, T5 consistently displayed the lowest counts for Spore Formers Bacterial Unit (3.84). After extended storage, a control treatment exhibited new peaks at 1792 cm^-1 and 1175 cm^-1 suggested chemical changes, potentially carbonyl-containing compounds. These findings may have significant implications for sustainable agricultural practices and the utilization of compost tea as an environmentally friendly soil amendment. [ABSTRACT FROM AUTHOR]

Energy storage technology plays a critical role in integrating variable energy sources into the grid and ensuring energy consistency. Electrochemical supercapacitors are one of the most promising energy storage devices, as they present multiple advantages of high power density, rapid charge/discharge characteristics, and long‐term cycle stability. Herein, the NiCo2O4/molybdate nanocomposites are developed as electrode materials for supercapacitor applications. The NiCo2O4/molybdate nanocomposites are synthesized by a facile single‐pot hydrothermal method and are coated on a carbon cloth substrate to form flexible supercapacitor electrodes. The structures, chemical compositions, morphologies, and textural properties of these materials are carefully studied by X‐Ray diffraction, X‐Ray absorption spectroscopy, scanning electron microscopy/energy‐dispersive X‐Ray spectroscopy mapping, and N2 adsorption–desorption isotherms. The formation of spinel NiCo2O4 nanorods decorated with molybdate (AMoO4, A = Co, Ni) particles is confirmed for all samples. The NiCo2O4/CoMoO4 electrode exhibits pseudocapacitive behavior and provides the highest specific capacitance (287.28 F g−1 at current density 6 A g−1), about 5.5 times as high as that of NiCo2O4, with excellent cycle stability (107% specific capacitance retention after 1000 charge/discharge cycles at 1 A g−1). Therefore, the NiCo2O4/CoMoO4 composites can be considered as a promising pseudocapacitor electrode material. [ABSTRACT FROM AUTHOR]

This study delves into the impact of lithium (Li3+) and silver (Ag7+) ion irradiation on the structure and luminescence of Dy3+ doped and Dy3+/Eu3+ co-doped Gd2MoO6 phosphors, synthesized via the hydrothermal method. To explore the influence of ions with varied mass and energy, 30 MeV Li3+ and 100 MeV Ag7+ ions were employed at different fluences. We elucidate the induced effects based on defect formation and the role of these ions' linear energy transfer (LET) within the irradiated material. SRIM software estimates the depth profile of the ions. Irradiation of the Gd2MoO6 phosphors with Li3+ and Ag7+ ions resulted in the formation of disordered lattices or tracks, modifying their structural, optical, and luminescence properties, which were analyzed by various techniques, including X-ray diffraction, scanning electron microscopy, diffuse reflectance, and photoluminescence. Thermoluminescence (TL) tests and calculations of trapping parameters were conducted to evaluate the dosimetric potential. The findings reveal a more pronounced effect of silver ions compared to lithium ions on the structural and luminescence behavior of doped and codoped Gd2MoO6 phosphors due to their higher atomic weight. [ABSTRACT FROM AUTHOR]

ModA is a soluble periplasmic molybdate-binding protein found in most gram-negative bacteria. It is part of the ABC transporter complex ModABC that moves molybdenum into the cytoplasm, to be used by enzymes that carry out various redox reactions. Since there is no clear analog for ModA in humans, this protein could be a good target for antibacterial drug design. Backbone 1H, 13C and 15N chemical shifts of apo and molybdate-bound ModA from E. coli were assigned at pHs 6.0 and 4.5. In addition, side chain atoms were assigned for apo ModA at pH 6.0. When comparing apo and molybdate-bound ModA at pH 6.0, large chemical shift perturbations are observed, not only in areas near the bound metal, but also in regions that are distant from the metal-binding site. Given the significant conformational change between apo and holo ModA, we might expect the large chemical shift changes to be more widespread; however, since they are limited to specific regions, the residues with large perturbations may reveal allosteric sites that could ultimately be important for the design of antibiotics that target ModA. [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]

Near-infrared (NIR) luminescence in Bi3ScMo2O12 is reported for the first time. Lanthanides Nd3+ and Yb3+ are used to obtain near-infrared emission. Characteristic NIR emission from Nd3+ was observed in the form of lines around 897 and 1068 nm. Yb3+ by itself did not show any PL. However, by virtue of Nd3+ → Yb3+ energy transfer, characteristic emission of Yb3+ could be obtained. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) luminescence in Bi3ScMo2O12 is reported for the first time. Lanthanides Nd3+ and Yb3+ are used to obtain near-infrared emission. Characteristic NIR emission from Nd3+ was observed in the form of lines around 897 and 1068 nm. Yb3+ by itself did not show any PL. However, by virtue of Nd3+ → Yb3+ energy transfer, characteristic emission of Yb3+ could be obtained. [ABSTRACT FROM AUTHOR]

The increasing use of molybdate has raised concerns about its potential toxicity in humans. However, the potential toxicity of molybdate under the current level of human exposure remains largely unknown. Endogenous metabolic alterations that are caused in humans by environmental exposure to pollutants are associated with the occurrence and progression of many diseases. This study exposed eight-week-old male C57 mice to sodium molybdate at doses relevant to humans (0.01 and 1 mg/kg/day) for eight weeks. Inductively coupled plasma mass spectrometry (ICP-MS) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) were utilized to assess changes in urine element levels and serum metabolites in mice, respectively. A total of 838 subjects from the NHANES 2017–2018 population database were also included in our study to verify the associations between molybdenum and cadmium found in mice. Analysis of the metabolome in mice revealed that four metabolites in blood serum exhibited significant changes, including 5-aminolevulinic acid, glycolic acid, l-acetylcarnitine, and 2,3-dihydroxypropyl octanoate. Analysis of the elementome revealed a significant increase in urine levels of cadmium after molybdate exposure in mice. Notably, molybdenum also showed a positive correlation with cadmium in humans from the NHANES database. Further analysis identified a positive correlation between cadmium and 2,3-dihydroxypropyl octanoate in mice. In conclusion, these findings suggest that molybdate exposure disrupted amino acid and lipid metabolism, which may be partially mediated by molybdate-altered cadmium levels. The integration of elementome and metabolome data provides sensitive information on molybdate-induced metabolic disorders and associated toxicities at levels relevant to human exposure. [ABSTRACT FROM AUTHOR]

Fly ash (FA) was used successfully as a carrier for the corrosion inhibitor molybdate and applied as an extender pigment in an epoxy coating. To enhance interaction, molybdate was attached to FA through intercalation in layered double hydroxide (LDH), facilitated by surface modification of FA. Molybdate was incorporated into LDH either via direct synthesis or ion exchange. Directly synthesized LDH significantly increased molybdate storage in FA. The FA-inhibitor combination was tested in three ways: molybdate release kinetics, corrosion of an ultra-low carbono (ULC) steel in chloride solution, protection of ULC steel conferred by particles embedded in an epoxy coating. Short-term molybdate release was favored by ion exchange, long-term release by deglomeration of LDH. ULC steel corrosion inhibition in 0.1 M NaCl reached 89%. Incorporating the material into epoxy coatings mitigated steel corrosion, validated by electrochemical impedance spectroscopy. This study underscores the efficacy of FA-LDH-molybdate systems in corrosion protection.

The title compound dipotassium gadolinium(III) phosphate(V) molybdate(VI), K2Gd(PO4)(MoO4), was synthesized from a high-temperature melt starting from GdF3 as a source of gadolinium. Its structure is isotypic with other MI2MIII(MVIO4)(PO4) compounds, where MI = Na, K or Cs, and MIII = rareearth cation, MVI = Mo orW. The three-dimensional framework is built up from [Gd(PO4)(MoO4)] anionic sheets, which are organized by adhesion of [GdPO4] layers and [MoO4] tetrahedra stacked above and below these layers. The interstitial space is occupied by K cations having eightfold oxygen coordination. The polyhedron of GdO8 was estimated to be a triangular dodecahedron by the continuous shape measurement method. [ABSTRACT FROM AUTHOR]

The title compound dipotassium gadolinium(III) phosphate(V) molybdate(VI), K2Gd(PO4)(MoO4), was synthesized from a high-temperature melt starting from GdF3 as a source of gadolinium. Its structure is isotypic with other MI2MIII(MVIO4)(PO4) compounds, where MI = Na, K or Cs, and MIII = rareearth cation, MVI = Mo orW. The three-dimensional framework is built up from [Gd(PO4)(MoO4)] anionic sheets, which are organized by adhesion of [GdPO4] layers and [MoO4] tetrahedra stacked above and below these layers. The interstitial space is occupied by K cations having eightfold oxygen coordination. The polyhedron of GdO8 was estimated to be a triangular dodecahedron by the continuous shape measurement method. [ABSTRACT FROM AUTHOR]

In diesem Versuch wird der Sauerstoff, welcher durch den katalytischen Zerfall von Wasserstoffperoxid gewonnen wird, für eine vollständige Verbrennung genutzt. Ob als motivierender Einstieg oder Schülerexperiment, die Nudelrakete bietet im Unterricht viele Anknüpfpunkte: im breiten Themenbereich rund um Sauerstoff, beim Brandschutz, in der Energetik und auch in Schülerprojekten, die einen Blick über den Tellerrand der Schulchemie werfen. [ABSTRACT FROM AUTHOR]

This paper reviews not the largest, but at the same time quite an interesting, group of natural and synthetic uranyl molybdate compounds. Nowadays, nine minerals of U and Mo are known, but the crystal structures have only been reported for five of them. Almost an order of magnitude more (69) synthetic compounds are known. A significant discrepancy in the topological types for natural and synthetic phases is shown, which is most likely due to elevated temperatures of laboratory experiments (up to 1000 °C), while natural phases apparently grow at significantly lower temperatures. At the same time, the prevalence of dense topologies (with edge-sharing interpolyhedral linkage) among natural phases can be noted, which is fully consistent with other recently considered mineral groups. Uranyl molybdates demonstrate several similarities with compounds of other U-bearing groups; however, even topological matches do not lead to the appearance of completely isotypic compounds. Structural complexity calculations confirm, in general, crystal chemical observations. Considering the prevalence of dense structures in which coordination polyhedra of uranium and molybdenum are connected through common edges as well as framework architectures, one can expect a less significant influence of interlayer species on the formation of the crystal structure than the main U-bearing complexes. The more structural complexity of the uranyl molybdate units, the more complex of the entire crystal structure is. In addition, there is a tendency for complexity to increase with increasing density of the complex; the simplest structures are vertex-shared, while the complexity increases with the appearance of common edges. [ABSTRACT FROM AUTHOR]

The title compound dipotassium gadolinium(III) phosphate(V) molybdate(VI), K2Gd(PO4)(MoO4), was synthesized from a high-temperature melt starting from GdF3 as a source of gadolinium. Its structure is isotypic with other MI2MIII(MVIO4)(PO4) compounds, where MI = Na, K or Cs, and MIII = rare-earth cation, MVI = Mo or W. The three-dimensional framework is built up from [Gd(PO4)(MoO4)] anionic sheets, which are organized by adhesion of [GdPO4] layers and [MoO4] tetrahedra stacked above and below these layers. The interstitial space is occupied by K cations having eightfold oxygen coordination. The polyhedron of GdO8 was estimated to be a triangular dodecahedron by the continuous shape measurement method.

Molybdenum is an essential element in the form of the molybdenum cofactor (Moco). In humans, Moco is required for four enzymes: xanthine oxidase (XO), aldehyde oxidase, sulfite oxidase (SO), and mitochondrial amidoxime-reducing component (mARC). The enzymes are involved in the oxidation of purines to uric acid, metabolism of aromatic aldehydes and heterocyclic compounds, and in the catabolism of sulfur amino acids. Molybdenum cofactor deficiency is a rare autosomal recessive syndrome due to a defective synthesis of Moco, resulting in a deficiency of all the molybdoenzymes. There are no reports on clinical signs of dietary molybdenum deficiency in otherwise healthy humans. Water-soluble molybdate is efficiently absorbed from the digestive tract. The body retention is regulated by urinary excretion. Plasma molybdenum reflects long-term intake and 24-h urinary excretion is related to recent intake. There are no biochemical markers of molybdenum status. Cereal products are the main contributors to molybdenum dietary intake, estimated to 100–170 μg/day in Nordic studies. Little data are available on molybdenum toxicity in humans. A tolerable upper intake level of molybdenum has been based on reproductive toxicity in rats, but the effects have not been reproduced in more recent studies. The U.S. Institute of Medicine (IOM, present National Academy of Sciences, Engineering, and Medicine; NASEM) established a Recommended Dietary Allowance of 45 μg/day in adult men and women in 2001, based on a small study reporting urinary excretion in balance with intake at 22 μg/day. The European Food Safety Authority (EFSA) considered in 2013 the evidence to be insufficient to derive an Average Requirement and a Population Reference Intake, but proposed an Adequate Intake of 65 μg/day for adults.

The molybdate-incorporated hydrotalcite-type α-Ni(OH)2 catalysts were prepared by the post-synthesis method. The synthesized catalyst was thoroughly studied using several physicochemical characterization methods. The catalytic activity of the material was studied on biomass model compounds such as anisole hydrotreating and the oxidation of iso-eugenol. The catalyst shows a significant conversion for the anisole hydrotreating in vapour phase conditions, yielding a steady-state conversion of 30% even after 10 h of time-on-stream (TOS). The primary product was benzene, with other products, viz., methyl anisole, methylcyclohexane, and toluene, as minor components. The catalyst also has the potential for iso-eugenol oxidation and shows 76.1% conversion with 75.5% selectivity for vanillin at 100 °C, 5 h. Molybdate-incorporated hydrotalcite-type α-Ni(OH)2 catalysts have the potential for oxidation of iso-eugenol to vanillin in the presence of an oxidant in a liquid phase and hydro-deoxygenation in the vapour phase under a hydrogen atmosphere. [ABSTRACT FROM AUTHOR]

To improve the tribological characteristics of materials employed in spatial mechanisms, there is a significant requirement to develop solid lubricating composites with superior performance. This study investigates the tribological characteristics of composites consisting of a nickel matrix combined with silver molybdate and barium molybdate. The experimental analysis focuses on evaluating the tribological behaviors of these composites from 25 °C to 800 °C. The findings indicate that the combined application of silver molybdate and barium molybdate resulted in enhanced self-lubricating properties of the composites, particularly at temperatures over 400 °C. The inclusion of both silver molybdate and barium molybdate in the composite resulted in the achievement of a low friction coefficient (0.34–0.5), as well as a wear rate ranging from 0.47 to 1.25 × 10−4 mm3 N−1m−1, within the temperature range of 400 to 800 °C. Furthermore, an analysis was conducted to examine the wear processes of the composites at various sliding temperatures. This analysis was based on the evaluation of the chemical composition and morphologies of the sliding surfaces, which were verified by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. [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]

Klebsiella pneumoniae , a facultative anaerobe, relies on acquiring molybdenum to sustain growth in anaerobic conditions, a crucial factor for the pathogen to establish infections within host environments. Molybdenum plays a critical role in pathogenesis as it forms an essential component of cofactors for molybdoenzymes. K. pneumoniae utilizes the ABC (ATP-Binding-Cassette) transporter encoded by the modABC operon for uptake of the group VI elements molybdenum and tungsten. In this study, we determined the X-ray crystal structures of both the molybdenum-free and molybdenum-bound substrate-binding protein (SBP) ModA from Klebsiella pneumoniae to 2.00 Å and 1.77 Å resolution respectively. ModA crystallizes in the space group P222 with a single monomer in one asymmetric unit. The purified protein remained soluble and specifically bound molybdate and tungstate with K d values of 6.3 nM and 5.2 nM, respectively. Tungstate competes with molybdate by binding to ModA, resulting in enhanced antimicrobial activity. These data provide a starting point for structural and functional analyses of molybdate transport in K. pneumoniae. • We determined the 2.0 Å crystal structure of K. pneumoniae ModA. • A molybdate-bound structure reveals the residues required for binding molybdenum. • Molybdate and tungstate bind with similarly high affinity to ModA. • ModA is a potential target for therapeutic intervention using tungstate. [ABSTRACT FROM AUTHOR]

There are many model experiments on catalysis for chemistry lessons. Most of them focus on the energetic aspects of catalysis. In lower school classes it makes sense to also create visual access to the reaction path, because this is the cause of the lower activation energy. With the trace element molybdenum as a catalyst, intermediate compounds in the reaction path can be visually recognized. They can also be safely isolated and can be used for school experiments. [ABSTRACT FROM AUTHOR]

Wastewater from the uranium mining industry contains toxic arsenate (AsO43–), selenate (SeO42–), and molybdate (MoO42–) that can be removed by complexation with MgAlFe(III)CO3SO4 hydrotalcites, yet underlying mechanisms are poorly known. Here, we studied complexation by K–edge Extended X-ray Absorption Fine Structure Spectroscopy, Density Functional Theory, Powder X-ray Diffraction, and Infrared and Raman Spectroscopy. We found that single shell paths with a coordination number of 4 and bond lengths of As–O = 1.69 Å, Se–O = 1.65 Å and Mo–O = 1.76 Å were best fitted for As–MgAlFe, Se–MgAlFe, and Mo–MgAlFe hydrotalcites. We observed a single antisymmetric υ3 band with no splitting at 821 cm−1 for AsO43–, 856 cm−1 for SeO42–, and 852 cm−1 for MoO42–. In all cases, basal (d003) and interlayer (d006) spacings before and after anion adsorption varied by less than 0.1 Å. Therefore, our findings demonstrate that arsenate, selenate, molybdate form outer-sphere-like complexes with MgAlFe hydrotalcite, and that these complexes are surface-bound and not intercalated. [ABSTRACT FROM AUTHOR]

Distinguishing the respective contributions of various microbes to methylmercury (MeHg) production is critical for predicting MeHg bioaccumulation and exposure risk. Metabolic inhibitors have been commonly used to block the activity of specific microbial groups and identify primary Hg methylating microbes. By reviewing literatures and our empirical data, we demonstrate how multiple factors, including (1) the addition of inappropriate amounts of inhibitors, (2) a tendency to overlook microbial syntrophy, and (3) the absence of comprehensive proxy systems of Hg methylation, would impact result interpretation of this approach. We thus suggest that the design of inhibition assays should consider the environmental properties, e.g., background levels of electron acceptors, concentrations of metabolic substrates, and abundances of Hg methylating microbes. We also recommend that inhibitors should be added at multiple concentrations and that observed changes in Hg methylation should be assessed with comprehensive indicators. Revealing the key factors responsible for the improper usage of this method and inadequate interpretation of the results would help optimize inhibition assays for robust predictions of MeHg production in nature. [ABSTRACT FROM AUTHOR]

The increasing use of molybdate has raised concerns about its potential toxicity in humans. However, the potential toxicity of molybdate under the current level of human exposure remains largely unknown. Endogenous metabolic alterations that are caused in humans by environmental exposure to pollutants are associated with the occurrence and progression of many diseases. This study exposed eight-week-old male C57 mice to sodium molybdate at doses relevant to humans (0.01 and 1 mg/kg/day) for eight weeks. Inductively coupled plasma mass spectrometry (ICP-MS) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) were utilized to assess changes in urine element levels and serum metabolites in mice, respectively. A total of 838 subjects from the NHANES 2017–2018 population database were also included in our study to verify the associations between molybdenum and cadmium found in mice. Analysis of the metabolome in mice revealed that four metabolites in blood serum exhibited significant changes, including 5-aminolevulinic acid, glycolic acid, l-acetylcarnitine, and 2,3-dihydroxypropyl octanoate. Analysis of the elementome revealed a significant increase in urine levels of cadmium after molybdate exposure in mice. Notably, molybdenum also showed a positive correlation with cadmium in humans from the NHANES database. Further analysis identified a positive correlation between cadmium and 2,3-dihydroxypropyl octanoate in mice. In conclusion, these findings suggest that molybdate exposure disrupted amino acid and lipid metabolism, which may be partially mediated by molybdate-altered cadmium levels. The integration of elementome and metabolome data provides sensitive information on molybdate-induced metabolic disorders and associated toxicities at levels relevant to human exposure.

Transition metal oxides with two different cations in the same crystal structure are considered to perform better as catalysts due to the synergistic effects causing better charge transfer and the availability of more active sites. Chemicals with molybdate anion (MoO4−) have been proven to have vast industrial importance in arenas like catalysis, supercapacitance, nuclear medicine, calorimetry, etc. In particular, nanostructured nickel molybdate (NiMoO4) is a promising entrant as an electrode substance for sophisticated power bank applications, apart from being a catalyst for chemical reactions involving energy conversion. Engineering of NiMoO4 at different scopes has been proven to cause a vast enhancement in the catalytic performance of nanometric NiMoO4 through improvement in redox reaction kinetics during the last couple of decades. This review imparts a precise thought about NiMoO4 considering all its developments in the unearthing of properties, synthesis routes, and analyzing tunability for improvement in attributes towards focused applications. [ABSTRACT FROM AUTHOR]

Translation abstract In this experiment, the oxygen obtained via the catalytic decomposition of hydrogen peroxide is used for complete combustion. Whether as a motivating introduction or as a student experiment, the pasta rocket offers many links to the classroom: in the broad subject area surrounding oxygen, in fire prevention, in energetics and in student projects that allow a look beyond the horizons of school chemistry. [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 hydrothermal preparation of active MnO2 via KMnO4 and MnSO4.H2O as inorganic forerunners is demonstrated, and it is evaluated as an adsorbent for the 99Mo produced by 235U fission. The structure and morphology of MnO2 were distinguished using various methods such as FTIR spectrum, FESEM, EDX, XRD, TGA. The 99Mo adsorption conduct on active manganese oxide was investigated, and the Mo uptake capacity was determined using static and dynamic techniques, and it was found to be 22.8 ± 1 and 6.72 ± 0.3 mg/g MnO2, respectively. This sorbent material was used in preliminary studies to prepare a 99Mo/99mTc generator. 99mTc eluted from the prepared generator was estimated to be 78–82 % with a low 99Mo breakthrough (0.002 %) and acceptable radiochemical, radionuclidic, and chemical purities. [ABSTRACT FROM AUTHOR]

Vitrification is currently the primary choice worldwide for high-level nuclear waste immobilization. This study investigated the crystallization behaviors of glasses containing 24%(mass fraction) and 30% simulated high-level nuclear waste, respectively, under different temperatures. According to X-ray diffraction, Raman spectroscopy and scanning electronic microscopy results, dendritic powellite(CaMoO4) phase and string-like Zr-cerianite (ZrxCe1-xO2) are the main crystalline phases when the glasses are heat treated at 800 ℃, while a great amount of hollow hexagonal oxyapatite(Ca2Ln8(SiO4)6O2) phases are observed in addition when the glasses are heated at 950 ℃. The chemical durability test shows that the heat treatment decreases the total normalized leaching mass loss of glass by about 1/3, with main contributions from B, Na, Mo and Ca. The normalized leaching mass loss of the glasses after heat treatment at 950 ℃ is smaller than that after heat treatment at 800 ℃. It indicates that the heat treatment of glass for crystallization improves glass durability.

Graphene oxide (GO) nanosheets were in-situ functionalized via polypyrrole (POP) nanoparticles using ammonium persulfate and afterward doped with sodium molybdate (GPM) and finally incorporated into the epoxy resin for achieving a nano-composite coating with dual barrier and self-healing properties. The synthesized nanoparticles were characterized by field-emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), and thermal gravimetric analysis (TGA) techniques. The release mechanism of the inhibitors from the GPM was investigated in both solution and coating phases. In addition, the modified coatings were tested electrochemically using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization as well as the pull-off test, cathodic disbonding, and salt spray. Results from FE- SEM /EDS, FT-IR, TGA, and XRD investigations supported the successful synthesis of the GPM complex and molybdate adsorption on the surface of GP. Electrochemical measurements revealed that the release of MoO4−2 from GPM resulted in the creation of a compact protective layer on the steel surface, enhanced inhibitive ability, and a low corrosion rate (1.41 A cm−2). It was shown that the charge transfer resistance of the bare steel sample in the blank solution enhanced from 2360 Ω cm2 to 8530 Ω cm2 in the presence of GPM after 1 h immersion time. The epoxy coating's ability to prevent corrosion was also improved by the GPM nanoparticles, reaching 99%.

In this work, a simple and sensitive electrochemical sensor was proposed for the detection of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity. Firstly, the BACE1 specific peptide was modified onto the Au electrode to graft a single-strand DNA with polycytosine DNA sequence (dC12) via amide bonding between peptide and dC12. Because the dC12 is abundant in phosphate groups, thus it can react with molybdate to form redox molybdophosphate, which can generate electrochemical current. Using BACE1 as a model peptidase, the proposed sensor shows a linear response range from 1 to 15 U/mL and limit of detection down to 0.05 U/mL. The sensor displays good performance for the BACE1 activity detection in human serum samples, which may have potential applications in the clinical diagnostics of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Industrial wastewater is the main source of an excessive amount of molybdenum (Mo) in natural ecosystems. It is necessary to remove Mo from wastewater before it is discharged into the environment. Molybdate ion(VI) is the most common form of Mo in natural reservoirs and industrial wastewater. In this work, the sorption removal of Mo(VI) from an aqueous medium was evaluated using aluminum oxide. The influence of such factors as the pH of the solution and the temperature was evaluated. Three adsorption isotherms, namely, Langmuir, Freundlich and Temkin, were used to describe the experimental results. It was found that the pseudo-first order kinetic model better fits the kinetic data of the adsorption process, and the maximum Mo(VI) adsorption capacity was 31 mg/g at 25 °C and pH 4. The thermodynamic parameters indicated that the process of Mo(VI) adsorption on Al2O3 was exothermic and spontaneous. It was shown that the adsorption of Mo strongly depends on pH. The most effective adsorption was observed at pH values below 7. Experiments on adsorbent regeneration showed that Mo(VI) can be effectively desorbed from the aluminum oxide surface into a phosphate solution in a wide range of pH values. After the desorption of Mo(VI) in a phosphate solution, alumina was found to be suitable for repeating the procedure at least five times. [ABSTRACT FROM AUTHOR]

Solid solutions K2Bi(PO4)(MoO4):Gd,Eu containing from 0.1 to 30 mole% of europium(III) and 0.1 mole% of gadolinium(III) have been prepared by conventional solid state reaction. The samples are characterized by X-ray powder diffraction method, IR and luminescence spectroscopies. It has been shown that doping with Eu3+ does not affect the symmetry of the layered framework. At room temperature, all the studied samples are characterized by intense red photoluminescence, which is associated with 5D0→7F0-4 emission transitions in Eu3+ ions. Due to the absence of concentration quenching and color characteristics, K2Bi(PO4)(MoO4):Gd,Eu has prominent prospects for application as a red phosphor. [ABSTRACT FROM AUTHOR]

It is urgent to develop a green synthesis approach for 2-nitro-4-methylsulfonylbenzoic acid (NMSBA) production as nitric acid oxidation procedure generates large amount of waste acid and nitrogen oxide. Herein, highly selective electrochemical oxidation of 2-nitro-4-methylsulfonyltoluene (NMST) was achieved under ambient pressure and temperature by employing molybdate as the catalyst and graphite rod as the anode. Through optimizing the catalyst dosage, phase transfer catalyst dosage, reactant concentration, electrolyte concentration, cell voltage and reaction time, the NMSBA selectivity of 95.16% was realized in acidic media with the NMST conversion of 57.37%. DFT calculations demonstrate that molybdate in the form of Mo2O72− can catalyze the oxidation of NMST in acidic media. NMST loses hydrogen from the methyl group, subsequently accepts oxygen, and finally converts into NMSBA. This work not only demonstrates molybdate as an efficient catalyst for the first time, but also provides a new electrochemical approach for highly selective production of NMSBA. [ABSTRACT FROM AUTHOR]

The mining and leakage of molybdenum (Mo) can cause environmental contamination which has not been realized until recently. Bacteria that can mitigate Mo-contamination was enriched and isolated. The low temperature and different pH conditions were considered to analysis its feasibility in Northern China which suffers from a long time of low temperatures every year. The result showed that the removal rate of MoO42− by Raoultella ornithinolytica A1 reached 30.46% at 25 °C and pH 7.0 in Luria–Bertani medium (LB). Meanwhile, A1 also showed some efficiency in the reduction of MoO42− in low phosphate molybdate medium (LPM), which reached optimum at the MoO42− concentration of 10 mM. The results of FTIR indicated that the cell wall performed an essential role in the MoO42− removal process, which was illustrated by the distribution of Mo in A1 (Mo bound to cell wall accounted for 92.29% of the total MoO42− removed). In addition, low temperature (10 °C) effect the removal rate of MoO42− by − 8.38 to 11.66%, indicating the potential for the in-situ microbial remediation of Mo-contaminated environments in low temperature areas. [ABSTRACT FROM AUTHOR]

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxicological effects of an AhR lacking the entire PASB structurally diverse chemicals, including halogenated aromatic hydrocarbons. Ligand-dependent transformation of the AhR into its DNA binding form involves a ligand-dependent conformational change, heat shock protein 90 (hsp90), dissociation from the AhR complex and AhR dimerization with the AhR nuclear translocator (ARNT) protein. The mechanism of AhR transformation was examined using mutational approaches and stabilization of the AhR:hsp90 complex with sodium molybdate. Insertion of a single mutation (F281A) in the hsp90-binding region of the AhR resulted in its constitutive (ligand-independent) transformation/DNA binding in vitro. Mutations of AhR residues within the Arg-Cys-rich region (R212A, R217A, R219A) and Asp371 (D371A) impaired AhR transformation without a significant effect on ligand binding. Stabilization of AhR:hsp90 binding with sodium molybdate decreased transformation/DNA binding of the wild type AhR but had no effect on constitutively active AhR mutants. Interestingly, transformation of the AhR in the presence of molybdate allowed detection of an intermediate transformation ternary complex containing hsp90, AhR, and ARNT. These results are consistent with a stepwise transformation mechanism in which binding of ARNT to the liganded AhR:hsp90 complex results in a progressive displacement of hsp90 and conversion of the AhR into its high affinity DNA binding form. The available molecular insights into the signaling mechanism of other Per-ARNT-Sim (PAS) domains and structural information on hsp90 association with other client proteins are consistent with the proposed transformation mechanism of the AhR.