Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.Aft...Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.After ingredient optimization,amorphous Co_(2)CeFe_(2)-MoO_(4) was identified as exhibiting the highest intrinsic activity among its counterparts.Modulation of electron structure enables Co_(2)CeFe_(2)-MoO_(4) to balance the adsorption behavior towards reactive intermediates.Ultimately,the obtained Co_(2)CeFe_(2)-MoO_(4) molybdate demonstrated a captivating OER performance,showcasing a low overpotential of 230 mV at 10 mA cm^(-2).Moreover,the alkaline electrolyzer employing the Co_(2)CeFe_(2)-MoO_(4) anode exhibited a low cell voltage of 1.50 V for water splitting and underwent an acceptable attenuation of 4.99% after 165 h of continuous operation,demonstrating its favorable catalytic activity and durability.This work provides a facile and eco-friendly synthesis pathway for crafting cost-effective and durable earth-abundant OER electrocatalysts tailored for water splitting to produce clean hydrogen.展开更多
A novel transition metal ion bridging bis（diphosphopentamolybdates） has been synthesized and characterized by elemental analysis,IR spectrum,UV spectrum and single-crystal X-ray diffraction.The single-crystal struct...A novel transition metal ion bridging bis（diphosphopentamolybdates） has been synthesized and characterized by elemental analysis,IR spectrum,UV spectrum and single-crystal X-ray diffraction.The single-crystal structure analysis shows that the compound consists of seven charge-compensating 2,2＇-biimidazole cations （BIIM=2,2＇-biimidazole） and one dumbbell-like [Mn（H2O）4（P2Mo5O23）2]10-heteropolyanion which is constructed by two [P2Mo5O23]6-clusters bridged through one [Mn（H2O）4]2＋ cation.展开更多
Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal cond...Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu（II） ions linked by three 3-（2-pyridyl）pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-（2-pyridyl）pyrazole ligands.Crystal data of 1：C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850（2）,b = 18.510（4）,c = 17.230（3） ,β = 100.57（3）°,V = 3401.6（12） 3,Z = 4,Dc = 2.324 g/cm3,F（000） = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775（Ⅰ 〉 2σ（Ⅰ））;Crystal data for 2：C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799（2）,b = 14.7970（13）,c = 23.141（2） ,β = 91.6180（10）°,V = 7119.0（11） 3,Z = 4,Dc = 2.077 g/cm3,F（000） = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696（Ⅰ〉 2σ（Ⅰ））.展开更多
A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated...A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated. The photoluminescence results show that all samples can be excited efficiently by UV （396 nm） light and blue （466 nm） light and emit red （615 nm） light with line spectra, which are coupled well with the characteristic emission from UV-LED and blue LED, respectively. The experimental results and their analysis suggest that the energy transfer occurs due to dipole-dipole interactions among Eu3＋ ions in LiKGd2-xEux（MoO4）4. Compared with Cao.8MoO4： Eu0.2^3-, the emission intensity of LiKGdo.9（MoO4）4： Eu1.1^3- is about 1.4 times higher and the CIE chromaticity coordinates are as close to the National Television System Committee （NTSC） standard values as those of Cao.8MoO4： Eu0.2^3-. The optical properties suggest that LiKGdo.9（MoO4）4： Eu1.1^3- is an efficient red-emitting phosphor for white LEDs applications.展开更多
Ar^+ ion bombardment induced reduction effect on Bi_2O_3, MoO_3 and Bi-Mo complex oxides, α-Bi_2Mo_3O_(13), β-Bi_2Mo_2O_9, and γ-Bi_2MoO_6, has been studied with XPS. The results show that, owing to the presence of...Ar^+ ion bombardment induced reduction effect on Bi_2O_3, MoO_3 and Bi-Mo complex oxides, α-Bi_2Mo_3O_(13), β-Bi_2Mo_2O_9, and γ-Bi_2MoO_6, has been studied with XPS. The results show that, owing to the presence of the oxygen anion bridge in Bi(Ⅲ)-O(Ⅱ)-Mo(Ⅵ), the reduction behavior of Bi(Ⅲ) and Mo(Ⅵ) metal ions in all the three complex oxides is contrary to that in the single oxides. While Mo(Ⅵ) in MoO_3 is reduced to Mo(Ⅵ) in UHV under Ar^+ ion bombardment, the valence state of Bi(Ⅲ) in Bi_2O_3 is unchanged. However, Bi(Ⅲ) in the three complex oxides is reduced to Bi(0) without noticeable reduction of Mo(Ⅵ). Nevertheless, the rates of Bi(Ⅲ) reduction are in correspondence with the difference in Bi/Mo atomic ratio and the crystallographic features of the three phases of bismuth molybdate are decreasing in the order of α-Bi_2Mo_3O_(12)≥β-Bi_2Mo_2O_9>γ-Bi_2MoO_6. A new O -species is observed on the bismuth molybdate surface reduced by Ar^+ ion bombardment.Wc discuss the above phenomena in the light of the crystallographic structure of bismuth molybdate. An electron transfer mechanism, based on the same electronic configuration suggested by Sleight in interpreting the mechanism for the catalytic reaction of selective oxidation of propylene, is proposed to interpret the ion-induced reduction and its reoxidation in oxidative atmosphere. Moreover, the reduction rates, observed in this work, parallel the catalytic activities of bismuth molybdates in propylene ammoxidation reaction, reported by Grassilli. So, it seems that both of the catalytic reaction and ion-induced reduction behavior of bismuth molybdates stem from a common origin of redox property which, in turn, is dictated by the solid state structure of the molybdates.展开更多
This study investigates the compatibility and efficacy of combining ammonium molybdate(AM)with antagonistic bacteria Bacillus amyloliquefaciens B10W10 and Pseudomonas sp.B11W11 for brown rot control(Monilinia laxa).In...This study investigates the compatibility and efficacy of combining ammonium molybdate(AM)with antagonistic bacteria Bacillus amyloliquefaciens B10W10 and Pseudomonas sp.B11W11 for brown rot control(Monilinia laxa).In vitro experiments reveal variable mycelial growth inhibition rates compared to untreated controls,with B11W11+0.5%AM and B10W10+2%AM displaying the highest inhibition rates after 5 days.After 10 days,the 2%AM+B10W10 combination exhibits the highest inhibition rate.Microscopic observations show structural alterations in mycelium within inhibition zones,marked by vacuolization.The antagonistic bacteria,alone or with different ammonium molybdate concentrations,significantly impact M.laxa spore germination,with the B10W10 cell filtrate+2%ammonium molybdate combination achieving the most substantial inhibition.Conversely,the 0.5%ammonium molybdate treatment has the lowest inhibition rate while the combination of AM and bacteria is giving better results compared to the use of bacteria alone.Fruits treated with various antagonistic bacteria and ammonium molybdate combinations demonstrate a significant reduction in disease severity.The 0.5%AM+B10W10 combination exhibits the lowest severity.FT-IR spectra analysis identifies shifts in fungal biomass functional groups,with reduced lignin-related bands and increased phenols,lipids,polysaccharides,and carbohydrates.This highlights the structural modifications caused by the biological treatments.The study also evaluates the effects on fruit quality parameters.The 2%ammonium molybdate treatment yields the lowest weight loss.TSS levels are affected by salt concentration,while acid content remains consistent across treatments.All treatments influence fruit firmness compared to controls.These findings emphasize the potential of combining ammonium molybdate and antagonistic bacteria for effective brown rot control,highlighting their compatibility and effects on disease severity,fungal biomass,spore germination,and fruit quality.展开更多
Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-dope...Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.展开更多
The design and development of high-performance anodes pose significant challenges in the construction of next-generation rechargeable lithium-ion batteries(LIBs).Sodium molybdate dihydrate(Na_(2)MoO_(4)·2H_(2)O)h...The design and development of high-performance anodes pose significant challenges in the construction of next-generation rechargeable lithium-ion batteries(LIBs).Sodium molybdate dihydrate(Na_(2)MoO_(4)·2H_(2)O)has garnered increasing attention due to its cost-effectiveness,non-toxicity and earth abundance.To enhance the Li storage performance of Na_(2)MoO_(4)·2H_(2)O,a crystallographic orientation regulation strategy is proposed in this work.Initially,density functional theory calculations are carried out to demonstrate that the(020)crystal plane of Na_(2)MoO_(4)·2H_(2)O offers the lowest energy barrier for Li^(+)migration.Subsequently,the preferred crystallographic orientation of Na_(2)MoO_(4)·2H_(2)O crystal is tuned through a low-temperature recrystallization method.Furthermore,the microstructure and phase changes of Na_(2)MoO_(4)·2H_(2)O during the lithiation/de-lithiation process are studied using in situ and ex situ XRD tests,ex situ XPS and cyclic voltammetry to unravel its Li^(+)storage mechanism.Upon application as LIBs anode,the Na_(2)MoO_(4)·2H_(2)O single-crystal particles with a preferred(020)surface exhibit superior reversible capacity,high-capacity retention and high cycling stability.The enhanced Li storage performance should be attributed to the regulated crystallographic orientation and small changes in the crystal microstructure during the charge/discharge process,which facilitates Li^(+)migration and bolsters structural stability.Notably,this study introduces a novel concept and a simple synthesis method for the advancement of electrodes in rechargeable batteries.展开更多
Traditional resistive semiconductor gas sensors suffer from high operating temperatures and poor selectivity.Thus,to address these issues,a highly selective nitrogen dioxide(NO_(2))sensor based on lead sulfide(PbS)qua...Traditional resistive semiconductor gas sensors suffer from high operating temperatures and poor selectivity.Thus,to address these issues,a highly selective nitrogen dioxide(NO_(2))sensor based on lead sulfide(PbS)quantum dots(QDs)–lead molybdate(PbMoO_(4))–molybdenum disulfide(MoS_(2))ternary nanocomposites operating at room temperature was fabricated herein.The ternary nanocomposites were synthesized using an in situ method,yielding Pb S QDs with an average size of~10 nm and PbMoO_(4)nanoparticles in the 10-to 20-nm range,uniformly distributed on ultrathin MoS_(2)nanosheets with an average thickness of~7 nm.The optimized sensor demonstrated a significant improvement in response to 1 ppm NO_(2)at 25℃,achieving a response of 44.5%,which was approximately five times higher than that of the pure MoS_(2)-based sensor(8.5%).The sensor also achieved relatively short response/recovery times and full recovery properties.Notably,the optimal sensor displayed extraordinary selectivity toward NO_(2),showing negligible responses to different interfering gases.Density functional theory(DFT)calculations were conducted to elucidate the underlying sensing mechanism,which was attributed to the enhanced specific surface area,the receptor function of both PbS QDs and PbMoO_(4)nanoparticles,and the transducer function of MoS_(2) nanosheets.展开更多
The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media...The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media is becoming increasingly urgent.This study reports a novel Yb^(3+),Er^(3+)co-doped KBa_(0.94)Ca_(0.06)Y(MoO_(4))_(3) (KBCYM)crystal.In this crystal,Yb^(3+)serves as a sensitizer,significantly enhancing the emission intensity of Er^(3+)in both visible and near-infrared bands.Notably,when the concentration of Yb^(3+)reaches 6 mol%,the emission intensity peaks at 1.55μm.Optical cross-section calculations reveal that the crystal exhibits a low laser pumping threshold at this concentration,demonstrating its potential as a laser gain medium.However,the crystal inevitably generates thermal effects during operation,which may adversely affect its performance.Therefore,real-time monitoring of the operating temperature is crucial.The thermal stability of the crystal was evaluated by measuring the temperature dependence of its luminescence intensity in the near-infrared band.Remarkably,even when the temperature rises to 553 K,the emission intensity at 1.55μm only decreases by 10.9%.Additionally,the temperature sensing performance was evaluated using fluorescence intensity ratio techniques,yielding absolute and relative sensitivities of 0.00981 K^(-1)at 453 K and 1.32%/K at 303 K,respectively,highlighting its potential for optical temperature sensing.Finally,through leveraging the unique properties of Yb^(3+),Er^(3+):KBCYM crystals,we successfully developed 1.55μm luminescent optical devices with practical applications.These devices not only exhibit efficient luminescent performance,but also possess a self-temperature measu rement functio n,opening up new avenues for the further development of laser technology.展开更多
Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence o...Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.展开更多
We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle siz...We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle size(70 nm).The crystal system is tetragonal phase and crystal lattice is body centered.The photo luminescence measurements including emission spectra,excitation spectra and fluorescence decay curves were carried out,elucidating that NaY(MoO4)2:Eu3+can be effectively excited by near UV and blue light.Moreover,it can be concluded that Eu3+energy transfer type is exchange interaction.Huang-Rhys factor and the critical energy transfer distance(Rc)were calculated to be 0.043 and 0.995 nm,respectively.Auzel’s model was used to obtain the intrinsic radiative transition lifetime of5 D0 level(τ0=0.923 ms).Furthermore,a calculation method was used to calculate refractive index n of nontransparent NaY(MoO4)2:1 mol%Eu3+phosphor,and n was obtained to be 1.86.展开更多
All of the samples were synthesized by sol-gel methods.Two approaches to charge compensation,（i） 2Ca2＋→Yb3＋＋M＋,where M＋ is an alkali ion like Li＋,Na＋ and K＋,and（ii） indirect charge compensation：3Ca2＋→2...All of the samples were synthesized by sol-gel methods.Two approaches to charge compensation,（i） 2Ca2＋→Yb3＋＋M＋,where M＋ is an alkali ion like Li＋,Na＋ and K＋,and（ii） indirect charge compensation：3Ca2＋→2Yb3＋＋vacancy,were studied in detail.It was found that charge compensation would be very beneficial for the growth of the grains,especially in Li＋ ions added samples.All the grains were homogeneously spherical with less boundaries;in addition,a great variety of the absorption ability in different charge compensation samples were observed：in comparison with the phosphors without charge compensation,indirectly charge compensated and Li＋ ions added phosphors showed much stronger absorption strength in the ultraviolet（UV） region whereas that of Na＋ and K＋ ions added samples was much weaker;moreover,measurements of the emission intensities showed that：in comparison with the phosphors without charge compensation,the visible emission intensity from MoO42-decreased a lot in indirectly charge compensated and Li＋ ions added phosphors,whereas there was a remarkable increase of the near infrared（NIR） emission intensity from Yb3＋ ions in the two types of samples under 266 nm excitation,implying more efficient energy transfer（ET） from MoO42-to Yb3＋ ions;at last,measurements and analysis of the decay curves of the visible 495 nm emission were carried out,and it was found that the energy transfer from MoO42-to Yb3＋ ions were more efficient in the two above types of phosphors.The theoretical quantum cutting（QC） efficiency was also improved greatly.Overall,the addition of Li＋ ions would be very beneficial for the morphology of the powders in addition to the growth of the grains.It was advantageous to increase the downconversion（DC） quantum efficiency;however,indirect charge compensation would enhance the NIR emission intensity to the most for its strongest absorption ability in the UV region.展开更多
A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperat...A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.展开更多
A simple way to prepare α- and β-CoMoO4 nanorods is reported in this paper. CoMoO4xH2O nanorod precursors were obtained using the microwave-assisted hydrothermal (MAH) method. By annealing the as-prepared CoMoO44xH2...A simple way to prepare α- and β-CoMoO4 nanorods is reported in this paper. CoMoO4xH2O nanorod precursors were obtained using the microwave-assisted hydrothermal (MAH) method. By annealing the as-prepared CoMoO44xH2O precursor at 600℃ for 10 min in a domestic microwave oven, α- and β-CoMoO4 nanorods were prepared. These powders were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform Raman microscopy and ultraviolet visible absorption spectroscopy (UV-vis spectra) as well as photoluminescence (PL) measurements. Based on the results, these materials revealed nanorod morphology. PL spectra obtained at room temperature for α- and β-CoMoO4 particles exhibited maximum components around the blue light emission. The results show that the domestic microwave oven has been successfully employed to obtain α- and β-CoMoO4 nanoparticles.展开更多
Solid-state reaction of praseodymium （III） oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr（MoO4）2. The structural and optical properties of the title compound h...Solid-state reaction of praseodymium （III） oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr（MoO4）2. The structural and optical properties of the title compound have been investigated by means of single-crystal X-ray diffraction and spectroscopic measurements at room temperature. KPr（MoO4）2 crystallizes in tetragonal,space group I41/a with a = 5.401（3）,c = 12.044（10）,Z = 2 and R （I 〉 2σ（I）） = 0.0416. It features the famous scheelite-type structure （CaWO4）,which can be thought as the substitution of two Ca^2＋ ions in CaWO4 by a couple of K^＋ and Pr^3＋ ions in a statistical manner,and W^6＋ by Mo^6＋ cations.展开更多
The Eu^3＋：BaMoO4 nanostructures were synthesized by a simple hydrothermal method,and characterized by XRD,transmission electron microscopy,high-resolution transmission electron microscopy,excitation and emission spe...The Eu^3＋：BaMoO4 nanostructures were synthesized by a simple hydrothermal method,and characterized by XRD,transmission electron microscopy,high-resolution transmission electron microscopy,excitation and emission spectra. Eu^3＋：BaMoO4 nanostructures show a lotus leaf-shaped morphology,and exhibit a strong red emission at 612 nm,which may afford an opportunity for the development of other nanostructure materials.展开更多
The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium coul...The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium could be preferentially adsorbed by the D403resin for4h in molybdate solution at a pH of approximately9.25.Separation factors,αVMo andαWMo,wereabove45and18,respectively,when the molar ratios of Mo/V and Mo/W in the solution exceeded40.Elution tests illustrated that vanadium and tungsten could be easily eluted from the resin with1mol/L sodium hydroxide solution in only1h.To further explore the sorption mechanism of the resin,the experimental equilibrium isotherm data of the three metals fitted well with the Freundlich model.The column experiments confirmed the adaptability of the D403resin in the production of sodium molybdate with a removal rate of tungsten surpassing90%and that of vanadium of99.4%.展开更多
This article investigated molybdenum recovery from oxygen pressure water leaching residue of Ni-Mo ore using alkaline leaching, followed by chemical treatment of leach liquor. Parameters affecting Mo leaching rate, su...This article investigated molybdenum recovery from oxygen pressure water leaching residue of Ni-Mo ore using alkaline leaching, followed by chemical treatment of leach liquor. Parameters affecting Mo leaching rate, such as sodium hydroxide concentration, reaction time, a liquid- to-solid ratio, and temperature for the preliminary alkaline leaching were experimentally determined. The results showed that more than 88 % of molybdenum was leached under the optimum conditions （2.5 ml.g-1 NaOH, 80 ℃, a liquid to solid ratio 3 ml.g-1, and reaction time 3 h）. After the purification of leach liquor, a CaMoO4 product of 99.2 % purity could be obtained by CaCla precipitation method. The whole Mo recovery reached about 82.7 %.展开更多
基金supported by the National Natural Science Foundation of China (No. 21872153)。
文摘Currently,endeavors to scale up the production of amorphous catalysts are still impeded by intricate synthesis conditions.Here,we have prepared a series of metal-based molybdate via one-step coprecipitation method.After ingredient optimization,amorphous Co_(2)CeFe_(2)-MoO_(4) was identified as exhibiting the highest intrinsic activity among its counterparts.Modulation of electron structure enables Co_(2)CeFe_(2)-MoO_(4) to balance the adsorption behavior towards reactive intermediates.Ultimately,the obtained Co_(2)CeFe_(2)-MoO_(4) molybdate demonstrated a captivating OER performance,showcasing a low overpotential of 230 mV at 10 mA cm^(-2).Moreover,the alkaline electrolyzer employing the Co_(2)CeFe_(2)-MoO_(4) anode exhibited a low cell voltage of 1.50 V for water splitting and underwent an acceptable attenuation of 4.99% after 165 h of continuous operation,demonstrating its favorable catalytic activity and durability.This work provides a facile and eco-friendly synthesis pathway for crafting cost-effective and durable earth-abundant OER electrocatalysts tailored for water splitting to produce clean hydrogen.
基金Supported by the Natural Science Foundation of Henan Province (No. 0611011900)
文摘A novel transition metal ion bridging bis（diphosphopentamolybdates） has been synthesized and characterized by elemental analysis,IR spectrum,UV spectrum and single-crystal X-ray diffraction.The single-crystal structure analysis shows that the compound consists of seven charge-compensating 2,2＇-biimidazole cations （BIIM=2,2＇-biimidazole） and one dumbbell-like [Mn（H2O）4（P2Mo5O23）2]10-heteropolyanion which is constructed by two [P2Mo5O23]6-clusters bridged through one [Mn（H2O）4]2＋ cation.
基金Supported by the 973 Key Program of the MOST (2006CB932904,2007CB815304)the National Natural Science Foundation of China (20873150,20821061,and 50772113)+2 种基金the Chinese Academy of Sciences (KJCX2-YW-M05)the Chinese Academy of Sciences (''Hundred Talents Program'') Ministry of Science and Technology of China (Project of ''973'' plan,No. 2007CB607606),and Shandong Provincial Education Department and Qilu Normal University
文摘Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu（II） ions linked by three 3-（2-pyridyl）pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-（2-pyridyl）pyrazole ligands.Crystal data of 1：C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850（2）,b = 18.510（4）,c = 17.230（3） ,β = 100.57（3）°,V = 3401.6（12） 3,Z = 4,Dc = 2.324 g/cm3,F（000） = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775（Ⅰ 〉 2σ（Ⅰ））;Crystal data for 2：C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799（2）,b = 14.7970（13）,c = 23.141（2） ,β = 91.6180（10）°,V = 7119.0（11） 3,Z = 4,Dc = 2.077 g/cm3,F（000） = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696（Ⅰ〉 2σ（Ⅰ））.
基金supported by the Major Science and Technology Projects of Wuhan City Science and Technology Bureau (Grant No.200810321148)
文摘A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated. The photoluminescence results show that all samples can be excited efficiently by UV （396 nm） light and blue （466 nm） light and emit red （615 nm） light with line spectra, which are coupled well with the characteristic emission from UV-LED and blue LED, respectively. The experimental results and their analysis suggest that the energy transfer occurs due to dipole-dipole interactions among Eu3＋ ions in LiKGd2-xEux（MoO4）4. Compared with Cao.8MoO4： Eu0.2^3-, the emission intensity of LiKGdo.9（MoO4）4： Eu1.1^3- is about 1.4 times higher and the CIE chromaticity coordinates are as close to the National Television System Committee （NTSC） standard values as those of Cao.8MoO4： Eu0.2^3-. The optical properties suggest that LiKGdo.9（MoO4）4： Eu1.1^3- is an efficient red-emitting phosphor for white LEDs applications.
基金Project supported by the National Natural Science Foundation of China
文摘Ar^+ ion bombardment induced reduction effect on Bi_2O_3, MoO_3 and Bi-Mo complex oxides, α-Bi_2Mo_3O_(13), β-Bi_2Mo_2O_9, and γ-Bi_2MoO_6, has been studied with XPS. The results show that, owing to the presence of the oxygen anion bridge in Bi(Ⅲ)-O(Ⅱ)-Mo(Ⅵ), the reduction behavior of Bi(Ⅲ) and Mo(Ⅵ) metal ions in all the three complex oxides is contrary to that in the single oxides. While Mo(Ⅵ) in MoO_3 is reduced to Mo(Ⅵ) in UHV under Ar^+ ion bombardment, the valence state of Bi(Ⅲ) in Bi_2O_3 is unchanged. However, Bi(Ⅲ) in the three complex oxides is reduced to Bi(0) without noticeable reduction of Mo(Ⅵ). Nevertheless, the rates of Bi(Ⅲ) reduction are in correspondence with the difference in Bi/Mo atomic ratio and the crystallographic features of the three phases of bismuth molybdate are decreasing in the order of α-Bi_2Mo_3O_(12)≥β-Bi_2Mo_2O_9>γ-Bi_2MoO_6. A new O -species is observed on the bismuth molybdate surface reduced by Ar^+ ion bombardment.Wc discuss the above phenomena in the light of the crystallographic structure of bismuth molybdate. An electron transfer mechanism, based on the same electronic configuration suggested by Sleight in interpreting the mechanism for the catalytic reaction of selective oxidation of propylene, is proposed to interpret the ion-induced reduction and its reoxidation in oxidative atmosphere. Moreover, the reduction rates, observed in this work, parallel the catalytic activities of bismuth molybdates in propylene ammoxidation reaction, reported by Grassilli. So, it seems that both of the catalytic reaction and ion-induced reduction behavior of bismuth molybdates stem from a common origin of redox property which, in turn, is dictated by the solid state structure of the molybdates.
基金supported by the Phytopathology Unit of the Department of Plant Protection(ENA-Meknes,Morocco).
文摘This study investigates the compatibility and efficacy of combining ammonium molybdate(AM)with antagonistic bacteria Bacillus amyloliquefaciens B10W10 and Pseudomonas sp.B11W11 for brown rot control(Monilinia laxa).In vitro experiments reveal variable mycelial growth inhibition rates compared to untreated controls,with B11W11+0.5%AM and B10W10+2%AM displaying the highest inhibition rates after 5 days.After 10 days,the 2%AM+B10W10 combination exhibits the highest inhibition rate.Microscopic observations show structural alterations in mycelium within inhibition zones,marked by vacuolization.The antagonistic bacteria,alone or with different ammonium molybdate concentrations,significantly impact M.laxa spore germination,with the B10W10 cell filtrate+2%ammonium molybdate combination achieving the most substantial inhibition.Conversely,the 0.5%ammonium molybdate treatment has the lowest inhibition rate while the combination of AM and bacteria is giving better results compared to the use of bacteria alone.Fruits treated with various antagonistic bacteria and ammonium molybdate combinations demonstrate a significant reduction in disease severity.The 0.5%AM+B10W10 combination exhibits the lowest severity.FT-IR spectra analysis identifies shifts in fungal biomass functional groups,with reduced lignin-related bands and increased phenols,lipids,polysaccharides,and carbohydrates.This highlights the structural modifications caused by the biological treatments.The study also evaluates the effects on fruit quality parameters.The 2%ammonium molybdate treatment yields the lowest weight loss.TSS levels are affected by salt concentration,while acid content remains consistent across treatments.All treatments influence fruit firmness compared to controls.These findings emphasize the potential of combining ammonium molybdate and antagonistic bacteria for effective brown rot control,highlighting their compatibility and effects on disease severity,fungal biomass,spore germination,and fruit quality.
文摘Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.
基金supported by the Natural Science Foundation of Guizhou Province(No.ZK 2022-044)the Platform of Science and Technology and Talent Team Plan of Guizhou Province(No.GCC[2023]007)+1 种基金the National Science Foundation of China(Nos.52101010 and 11964006)the Fund of Natural Science Special(Special Post)Research Foundation of Guizhou University(No.2021-018).
文摘The design and development of high-performance anodes pose significant challenges in the construction of next-generation rechargeable lithium-ion batteries(LIBs).Sodium molybdate dihydrate(Na_(2)MoO_(4)·2H_(2)O)has garnered increasing attention due to its cost-effectiveness,non-toxicity and earth abundance.To enhance the Li storage performance of Na_(2)MoO_(4)·2H_(2)O,a crystallographic orientation regulation strategy is proposed in this work.Initially,density functional theory calculations are carried out to demonstrate that the(020)crystal plane of Na_(2)MoO_(4)·2H_(2)O offers the lowest energy barrier for Li^(+)migration.Subsequently,the preferred crystallographic orientation of Na_(2)MoO_(4)·2H_(2)O crystal is tuned through a low-temperature recrystallization method.Furthermore,the microstructure and phase changes of Na_(2)MoO_(4)·2H_(2)O during the lithiation/de-lithiation process are studied using in situ and ex situ XRD tests,ex situ XPS and cyclic voltammetry to unravel its Li^(+)storage mechanism.Upon application as LIBs anode,the Na_(2)MoO_(4)·2H_(2)O single-crystal particles with a preferred(020)surface exhibit superior reversible capacity,high-capacity retention and high cycling stability.The enhanced Li storage performance should be attributed to the regulated crystallographic orientation and small changes in the crystal microstructure during the charge/discharge process,which facilitates Li^(+)migration and bolsters structural stability.Notably,this study introduces a novel concept and a simple synthesis method for the advancement of electrodes in rechargeable batteries.
基金supported by the National Natural Science Foundation of China(No.52274255)Fundamental Research Funds for the Central Universities,China(Nos.N2401003,N2301003,N2201008,N2201004,and N2301025)+3 种基金Liaoning Revitalization Talents Program,China(No.XLYC2202028)Postdoctoral Foundation of Northeastern University,ChinaYoung Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)China Postdoctoral Science Foundation(No.2022M720025)。
文摘Traditional resistive semiconductor gas sensors suffer from high operating temperatures and poor selectivity.Thus,to address these issues,a highly selective nitrogen dioxide(NO_(2))sensor based on lead sulfide(PbS)quantum dots(QDs)–lead molybdate(PbMoO_(4))–molybdenum disulfide(MoS_(2))ternary nanocomposites operating at room temperature was fabricated herein.The ternary nanocomposites were synthesized using an in situ method,yielding Pb S QDs with an average size of~10 nm and PbMoO_(4)nanoparticles in the 10-to 20-nm range,uniformly distributed on ultrathin MoS_(2)nanosheets with an average thickness of~7 nm.The optimized sensor demonstrated a significant improvement in response to 1 ppm NO_(2)at 25℃,achieving a response of 44.5%,which was approximately five times higher than that of the pure MoS_(2)-based sensor(8.5%).The sensor also achieved relatively short response/recovery times and full recovery properties.Notably,the optimal sensor displayed extraordinary selectivity toward NO_(2),showing negligible responses to different interfering gases.Density functional theory(DFT)calculations were conducted to elucidate the underlying sensing mechanism,which was attributed to the enhanced specific surface area,the receptor function of both PbS QDs and PbMoO_(4)nanoparticles,and the transducer function of MoS_(2) nanosheets.
基金Project supported by Jilin Provincial Department of Education(JJKH20230821KJ,JJKH20230822KJ,JJKH20230823KJ,JJKH20240930KJ,20240101107JC)。
文摘The 1.55μm laser technology is widely applied in military,information communication,biomedicine and other fields.With the deepening development of these application areas,the demand for novel 1.55μm laser gain media is becoming increasingly urgent.This study reports a novel Yb^(3+),Er^(3+)co-doped KBa_(0.94)Ca_(0.06)Y(MoO_(4))_(3) (KBCYM)crystal.In this crystal,Yb^(3+)serves as a sensitizer,significantly enhancing the emission intensity of Er^(3+)in both visible and near-infrared bands.Notably,when the concentration of Yb^(3+)reaches 6 mol%,the emission intensity peaks at 1.55μm.Optical cross-section calculations reveal that the crystal exhibits a low laser pumping threshold at this concentration,demonstrating its potential as a laser gain medium.However,the crystal inevitably generates thermal effects during operation,which may adversely affect its performance.Therefore,real-time monitoring of the operating temperature is crucial.The thermal stability of the crystal was evaluated by measuring the temperature dependence of its luminescence intensity in the near-infrared band.Remarkably,even when the temperature rises to 553 K,the emission intensity at 1.55μm only decreases by 10.9%.Additionally,the temperature sensing performance was evaluated using fluorescence intensity ratio techniques,yielding absolute and relative sensitivities of 0.00981 K^(-1)at 453 K and 1.32%/K at 303 K,respectively,highlighting its potential for optical temperature sensing.Finally,through leveraging the unique properties of Yb^(3+),Er^(3+):KBCYM crystals,we successfully developed 1.55μm luminescent optical devices with practical applications.These devices not only exhibit efficient luminescent performance,but also possess a self-temperature measu rement functio n,opening up new avenues for the further development of laser technology.
基金supported by Fundamental Research Funds for the Central Universities (2662014BQ061, 2015PY120, 2015PY047, 2016PY088)the National Natural Science Foundation of China (51572101, 21502059, 21607047)~~
文摘Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.
基金Project supported by the National Natural Science Foundation of China(51002041)
文摘We synthesized NaY(MoO4)2:Eu3+phosphors of different doping concentrations by a molten salt method.This facile way possesses advantages such as simple process,lower calcination temperature(350℃)and small particle size(70 nm).The crystal system is tetragonal phase and crystal lattice is body centered.The photo luminescence measurements including emission spectra,excitation spectra and fluorescence decay curves were carried out,elucidating that NaY(MoO4)2:Eu3+can be effectively excited by near UV and blue light.Moreover,it can be concluded that Eu3+energy transfer type is exchange interaction.Huang-Rhys factor and the critical energy transfer distance(Rc)were calculated to be 0.043 and 0.995 nm,respectively.Auzel’s model was used to obtain the intrinsic radiative transition lifetime of5 D0 level(τ0=0.923 ms).Furthermore,a calculation method was used to calculate refractive index n of nontransparent NaY(MoO4)2:1 mol%Eu3+phosphor,and n was obtained to be 1.86.
基金Project supported by the National Natural Science Foundation of China (10774140,11074245,11011120083)Knowledge Innovation Project of the Chinese Academy of Sciences (KJCX2-YW-M11)Special Foundation for Talents of Anhui Province,China (2007Z021)
文摘All of the samples were synthesized by sol-gel methods.Two approaches to charge compensation,（i） 2Ca2＋→Yb3＋＋M＋,where M＋ is an alkali ion like Li＋,Na＋ and K＋,and（ii） indirect charge compensation：3Ca2＋→2Yb3＋＋vacancy,were studied in detail.It was found that charge compensation would be very beneficial for the growth of the grains,especially in Li＋ ions added samples.All the grains were homogeneously spherical with less boundaries;in addition,a great variety of the absorption ability in different charge compensation samples were observed：in comparison with the phosphors without charge compensation,indirectly charge compensated and Li＋ ions added phosphors showed much stronger absorption strength in the ultraviolet（UV） region whereas that of Na＋ and K＋ ions added samples was much weaker;moreover,measurements of the emission intensities showed that：in comparison with the phosphors without charge compensation,the visible emission intensity from MoO42-decreased a lot in indirectly charge compensated and Li＋ ions added phosphors,whereas there was a remarkable increase of the near infrared（NIR） emission intensity from Yb3＋ ions in the two types of samples under 266 nm excitation,implying more efficient energy transfer（ET） from MoO42-to Yb3＋ ions;at last,measurements and analysis of the decay curves of the visible 495 nm emission were carried out,and it was found that the energy transfer from MoO42-to Yb3＋ ions were more efficient in the two above types of phosphors.The theoretical quantum cutting（QC） efficiency was also improved greatly.Overall,the addition of Li＋ ions would be very beneficial for the morphology of the powders in addition to the growth of the grains.It was advantageous to increase the downconversion（DC） quantum efficiency;however,indirect charge compensation would enhance the NIR emission intensity to the most for its strongest absorption ability in the UV region.
基金supported by the China Postdoctoral Science Foundation (No.20080430556)the Major State Basic Research and Development Program of China (No.2006CB705600)
文摘A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.
基金financial support of Brazilian agencies CNPq,FAPESP and CAPES.
文摘A simple way to prepare α- and β-CoMoO4 nanorods is reported in this paper. CoMoO4xH2O nanorod precursors were obtained using the microwave-assisted hydrothermal (MAH) method. By annealing the as-prepared CoMoO44xH2O precursor at 600℃ for 10 min in a domestic microwave oven, α- and β-CoMoO4 nanorods were prepared. These powders were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform Raman microscopy and ultraviolet visible absorption spectroscopy (UV-vis spectra) as well as photoluminescence (PL) measurements. Based on the results, these materials revealed nanorod morphology. PL spectra obtained at room temperature for α- and β-CoMoO4 particles exhibited maximum components around the blue light emission. The results show that the domestic microwave oven has been successfully employed to obtain α- and β-CoMoO4 nanoparticles.
基金Supported by the NNSFC (20373073)the National Basic Research Program of China (No. 2007CB815307)+2 种基金the Funds of CAS (KJCX2-YW-H01)Fujian Key Laboratory of Nanomaterials (No. 2006L2005)the Knowledge Innovation Program of CAS
文摘Solid-state reaction of praseodymium （III） oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr（MoO4）2. The structural and optical properties of the title compound have been investigated by means of single-crystal X-ray diffraction and spectroscopic measurements at room temperature. KPr（MoO4）2 crystallizes in tetragonal,space group I41/a with a = 5.401（3）,c = 12.044（10）,Z = 2 and R （I 〉 2σ（I）） = 0.0416. It features the famous scheelite-type structure （CaWO4）,which can be thought as the substitution of two Ca^2＋ ions in CaWO4 by a couple of K^＋ and Pr^3＋ ions in a statistical manner,and W^6＋ by Mo^6＋ cations.
基金Supported by the NNSFC (No. 60778035)the Key Project of Science and Technology of Fujian Province (2001F004)
文摘The Eu^3＋：BaMoO4 nanostructures were synthesized by a simple hydrothermal method,and characterized by XRD,transmission electron microscopy,high-resolution transmission electron microscopy,excitation and emission spectra. Eu^3＋：BaMoO4 nanostructures show a lotus leaf-shaped morphology,and exhibit a strong red emission at 612 nm,which may afford an opportunity for the development of other nanostructure materials.
基金Project(2014CB643405)supported by the National Basic Research Program of China
文摘The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium could be preferentially adsorbed by the D403resin for4h in molybdate solution at a pH of approximately9.25.Separation factors,αVMo andαWMo,wereabove45and18,respectively,when the molar ratios of Mo/V and Mo/W in the solution exceeded40.Elution tests illustrated that vanadium and tungsten could be easily eluted from the resin with1mol/L sodium hydroxide solution in only1h.To further explore the sorption mechanism of the resin,the experimental equilibrium isotherm data of the three metals fitted well with the Freundlich model.The column experiments confirmed the adaptability of the D403resin in the production of sodium molybdate with a removal rate of tungsten surpassing90%and that of vanadium of99.4%.
基金supported by the National High Technology Research and Development Program of China(No.2009AA06Z106)Yunnan Provincial Science and Technology Department of China(No.2011GA004)
文摘This article investigated molybdenum recovery from oxygen pressure water leaching residue of Ni-Mo ore using alkaline leaching, followed by chemical treatment of leach liquor. Parameters affecting Mo leaching rate, such as sodium hydroxide concentration, reaction time, a liquid- to-solid ratio, and temperature for the preliminary alkaline leaching were experimentally determined. The results showed that more than 88 % of molybdenum was leached under the optimum conditions （2.5 ml.g-1 NaOH, 80 ℃, a liquid to solid ratio 3 ml.g-1, and reaction time 3 h）. After the purification of leach liquor, a CaMoO4 product of 99.2 % purity could be obtained by CaCla precipitation method. The whole Mo recovery reached about 82.7 %.
