Phenol in waste water threatens human health and is difficultly to be decomposed by nature.Efficient degradation of high-loaded phenol in water under mild condition is still a great challenge.Herein,ionic liquids with...Phenol in waste water threatens human health and is difficultly to be decomposed by nature.Efficient degradation of high-loaded phenol in water under mild condition is still a great challenge.Herein,ionic liquids with tungstate anion were designed and prepared.It was found that dodecyltrimethylammonium tungstate could catalyzed degradation of phenol into gases and water thoroughly at 323 k in 8 h.Tungstate anion revealed good catalytic oxidative activity and long carbon chain group connecting with cation of ionic liquids enriched phenol around catalysts,which induced the complete degradation of phenol at mild conditions.Increasing the amounts of hydrogen peroxide benefited to the total degradation of phenol.In addition,the ionic liquid could be reused for its excellent thermal stability.Our work provided a different strategy to treat waste water containing phenol efficiently.展开更多
Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including ...Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.展开更多
AIM: To evaluate the effect of sodium tungstate on visual evoked potentials(VEPs) in diabetic rats.· METHODS: Wistar rats were randomly divided into three groups as normal control, diabetic control and diabetic r...AIM: To evaluate the effect of sodium tungstate on visual evoked potentials(VEPs) in diabetic rats.· METHODS: Wistar rats were randomly divided into three groups as normal control, diabetic control and diabetic rats treated with sodium tungstate. Diabetes was induced by single intraperitoneal injection of streptozotocin(50 mg/kg). Sodium tungstate [40 mg/(kg·d)]was administered for 12 wk and then VEPs were recorded.Additionally, thiobarbituric acid reactive substance(TBARS) levels were measured in brain tissues.·RESULTS: The latencies of P1, N1, P2, N2 and P3 waves were significantly prolonged in diabetic rats compared with control group. Diabetes mellitus caused an increase in the lipid peroxidation process that was accompanied by changes in VEPs. However, prolonged latencies of VEPs for all components returned to control levels in sodium tungstate-treated group. The treatment of sodium tungstate significantly decreased brain TBARS levels and depleted the prolonged latencies of VEP components compared with diabetic control group.· CONCLUSION: Sodium tungstate shows protective effects on visual pathway in diabetic rats, and it can be worthy of further study for potential use.展开更多
An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1 (C36H24 CuN6O19W6, Mr = 2011.20) was hydrothermally synthesized and characterized by single- crystal X-ray diffraction, IR spectrum, UV-VI...An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1 (C36H24 CuN6O19W6, Mr = 2011.20) was hydrothermally synthesized and characterized by single- crystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005(11), b = 11.2585(11), c = 20.2867(15) , β = 102.177(2)o, V = 4264.4 3, μ(MoKa) = 16.691 mm–1, Dc = 3.133 g/cm3, Z = 4, F(000) = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with I > 2σ(I). The result of structure determination shows that the crystal structure is constructed from [W6O19]2– cluster anions and [Cu(phen)3]2+ complex fragments, which are held together into a three-dimen- sional network through hydrogen-bonding interactions.展开更多
The expanded industrial experiments were conducted with practical industfial liquor to separate free alkali from sodium tungstate solution by electrolysis with canon-exchange membrane. Experimental results show that o...The expanded industrial experiments were conducted with practical industfial liquor to separate free alkali from sodium tungstate solution by electrolysis with canon-exchange membrane. Experimental results show that on the condition that the temperature is 50-55℃ and the current density is 1000 A/m2, the single electrolysis cell is operated stably and 80% free-alkali in mass fraction is separated from the anode feed liquor of sodium tungstate, with electric ef- ficiency up to more than 88% and the unit energy consumption E lower than 1900 kWh/t; while three electfolysis cells in series are operated, under the condition that the temperature is 60-65 ℃ and the current density is 1000 A/m2, the elec- tric efficiency can reach higher than 88% and the unit energy consumption E can be lower than 2250 kWh/t.展开更多
Xiao Liansheng Wang Wei Zhang Qixiu Gong Bofan Cao Jiashu (Department of Metallurgical Science and Engineering, Central South University of Technology, Changsha 410083, China) Abstrac By measuring the electrode polari...Xiao Liansheng Wang Wei Zhang Qixiu Gong Bofan Cao Jiashu (Department of Metallurgical Science and Engineering, Central South University of Technology, Changsha 410083, China) Abstrac By measuring the electrode polarization curves of many kinds of materials and life spans of electrodes through intensifying electrolysis in the process, the appropriate electrode materials for different stages of electrolysis of sodium tungstate solution with membrane have been selected The effects of the electrodes with different shapes on electrolysis have been investigated. The result shows that network electrode is more suitable to electrolysis of sodium tungstate solution.展开更多
The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungst...The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungstate are the aggregations of the tungsten oxide tetrahedrons and lead cations with various geometry configurations. It is suggested that the favorable growth units of lead tungstate crystal are pyramidal, tetragonal prism and quadrangular units corresponding to geometric orientations of the simple forms of the crystal. Under low restricted growth conditions, the growth form of lead tungstate crystallites is the aggregation of the geometric configurations of these favorable growth units. The above conclusions are completely confirmed by the experiment on hydrothermal preparation of lead tungstate crystallites.展开更多
A hydrogel possessing interesting photochromic behaviors was developed by in situ ultraviolet(UV)irradiation-assisted polymerization of an aqueous solution of N-isopropylacrylamide monomer in the presence of cesium tu...A hydrogel possessing interesting photochromic behaviors was developed by in situ ultraviolet(UV)irradiation-assisted polymerization of an aqueous solution of N-isopropylacrylamide monomer in the presence of cesium tungstate nanosheets.By this process,a hierarchical porous network structure was finely constructed while showing ultrahigh flexibility.More importantly,the newly prepared hydrogel retained the photochromic properties of the cesium tungstate nanosheets.The color transitions could be readily controlled by UV laser irradiation and were completely reversible via laser exposure or dark treatment.The nanocomposite hydrogel with its excellent photochromic properties and ultrahigh flexibility will have great applications in flexible photochromic devices.The synthetic procedure is simple and has promises to be extended to developing other hydrogels with various new functionalities.展开更多
The contamination of antibiotics in aqueous environment causes increasing concerns recently.Lightassisted activation of peroxydisulfate(PDS)has been demonstrated as an efficient technology for re moval of contaminatio...The contamination of antibiotics in aqueous environment causes increasing concerns recently.Lightassisted activation of peroxydisulfate(PDS)has been demonstrated as an efficient technology for re moval of contamination in water.Herein,a hollow sphere of CuWO_(4)(h-CuWO_(4))was employed as a visible lightactivated photocatalyst for the activation of PDS,and following with high removal efficiency(98%)of antibiotic sulfamethoxazole(SMX).Under visible light irradiation,the degradation rate on hollow structures system is nearly 2 times higher than the traditional solid CuWO_(4) spheres.Furthermore,the underlying mechanism and detailed pathway of SMX degradation were proposed based on density functional theory(DFT)calculations and liquid chromatography-mass spectrometry(LC-MS).This work provides a new feasible way for advanced oxidation processes to remove antibiotics SMX in heterogeneous system,and open up new application possibilities of CuWO_(4)-based materials.展开更多
This work presents the formation of butyl levulinate,a potential fuel additive,and an excellent renewable chemical obtained by the butanolysis of furfuryl alcohol(FAL)over a solid acid catalyst.The butanolysis of furf...This work presents the formation of butyl levulinate,a potential fuel additive,and an excellent renewable chemical obtained by the butanolysis of furfuryl alcohol(FAL)over a solid acid catalyst.The butanolysis of furfuryl alcohol reaction is a strong function of acidity for which tungstated zirconia(WO_(3)-ZrO_(2)),a robust solid acid catalyst,and a sulfonated carbon catalyst were employed to produce high yields of butyl levulinate targeting a lower initial molar ratio of butanol to FAL.A maximum of 28 mol%yield of butyl levulinate was obtained with tungstated zirconia catalyst.Easily prepared sulfonated carbon catalyst at high reaction temperatures facilitated the complete conversion of reaction intermediate,2-butoxymethylfuran(2-BMF)through which butyl levulinate was formed,and as high as 80 mol%of butyl levulinate yield was produced at an initial mole ratio of 8.5:1 of butanol to FAL.The better results of sulfonated carbon catalyst could be attributed to the presence of-SO3H,carboxylic acid,and phenolic OH groups on the carbon surface.展开更多
Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demon...Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.展开更多
The 10 at.% Er3+-doped KYb(WO4)2(KEr0.1Yb0.9(WO4)2) laser crystal with dimensions up to 25 mm×15 mm×10 mm was grown by the Kyropoulos method.The crystal structure was identified as β-KEr0.1Yb0.9(WO4)2 by XR...The 10 at.% Er3+-doped KYb(WO4)2(KEr0.1Yb0.9(WO4)2) laser crystal with dimensions up to 25 mm×15 mm×10 mm was grown by the Kyropoulos method.The crystal structure was identified as β-KEr0.1Yb0.9(WO4)2 by XRD analysis.Through TG-DTA curves,the melting point and transition point of the crystal were determined to be 1058 and 1031 °C,respectively.Infrared spectrum and Raman spectrum were measured,and the vibration frequencies of infrared and Raman active modes for the crystal were assigned.The absorption cross section is 3.1×10-20 cm2 at chief peak of 981 nm with the absorption line width of 26 nm.Based on the Judd-Ofelt theory,the intensity parameters ?λ(λ=2,4,6) calculated were:?2=16.34×10-20 cm2,?4=4.18×10-20 cm2,and ?6=1.26×10-20 cm2.There was a strong emission peak near 1533 nm and the emission line width at the main peak at 1533 nm run up to 55 nm with the emission cross section of 3.47×10-20 cm2 .These optical parameters indicated the potential of this crystal used as an excellent laser material for 1540 nm nearby human-eye safe.展开更多
Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and...Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and non-activated aro-matic compounds. The reactions were conducted under solvent-free conditions, which afforded good to excellent yields. The observed reaction times in MW assisted conditions are in the range of only few minutes.展开更多
Whereas the light yield of PWO crystal can be significantly improved by doping with either of F- and Sb3+, effects of heavily co-doping with by F-+Sb3+, F-+Ca2+, and F-+Ca2++Sb3+, respectively, on the properties of PW...Whereas the light yield of PWO crystal can be significantly improved by doping with either of F- and Sb3+, effects of heavily co-doping with by F-+Sb3+, F-+Ca2+, and F-+Ca2++Sb3+, respectively, on the properties of PWO scintillation crystals, including optical transmission, luminescence and light yield were studied. The result indicates that co-doping with three dopants, F-+Ca2++Sb3+, is a more effective measure than doping with single dopant F- for the improvement of scintillation properties of PWO crystals, including light yield.展开更多
The crystals of NaLn（WO4）<sub>2</sub>（Ln=La,Pr,Nd）are grown from a melt of LiCl-Na<sub>2</sub>WO<sub>4</sub> flux by slowcooling method.The chemical analysis data show that the ...The crystals of NaLn（WO4）<sub>2</sub>（Ln=La,Pr,Nd）are grown from a melt of LiCl-Na<sub>2</sub>WO<sub>4</sub> flux by slowcooling method.The chemical analysis data show that the crystals are NaLa（WO<sub>4</sub>）<sub>2</sub>,NaPr（WO4）<sub>2</sub> andNaNd（WO<sub>4</sub>）<sub>2</sub> respectively.The structures of the crystals are ascertained that they belong to scheelite structureof the tetragonal system with a space group of 14<sub>1</sub>/a.The lattice parameters of the crystals have beencalculated.It is found that the cell volume of NaLn（WO<sub>4</sub>）<sub>2</sub> crystals decrease with a decrease of Ln<sup>3+</sup>radius.The bond distances and their angles in NaLa（WO<sub>4</sub>）<sub>2</sub> and NaNd（WO<sub>4</sub>）<sub>2</sub> are given.It is found that inaccordance with the decrease of ionic radii of Ln<sup>3+</sup>due to increase of atomic number,the bond distances betweenLn-O,Ln-Ln and W-O decrease regularly.The infrared spectra of NaLn（WO<sub>4</sub>）<sub>2</sub> are measured.Thetetrahedra characteristic absorptions of WO<sub>4</sub><sup>2-</sup>are shown.The sensitization of host lattice is observed from theexcitation and fluorescent spectra of NaLa（WO<sub>4</sub>）<sub>2</sub> and NaPr（WO<sub>4</sub>）<sub>2</sub>.展开更多
The present paper reports new results regarding the addition of pseudo-boehmite as a binder during the synthesis of shaped Pt/WO_(3)-ZrO_(2)-Al_(2)O_(3) (PtWZA) catalysts. Binder shaping can noticeably influence not o...The present paper reports new results regarding the addition of pseudo-boehmite as a binder during the synthesis of shaped Pt/WO_(3)-ZrO_(2)-Al_(2)O_(3) (PtWZA) catalysts. Binder shaping can noticeably influence not only the structure and acidity of catalyst and improve its catalytic performance with regard to n-heptane isomerization, but the mechanical strength of the catalyst. A suitable binder content can improve the isomerization activity or selectivity by changing the acidity of PtWZA. The influence of the binder content depends on the WO_(3) content of the catalyst. PtWZA catalysts that contain 5%-15% binder on a dry basis exhibit favorable isomerization performance that depends on WO_(3) content. Suitable catalysts include Pt20WZ5A and Pt30WZ15A, which provide conversions of approximately 80%-90% and a selectivity of 90%. These new findings enrich researcher knowledge of the effect of the binder on the catalyst shaping process and are useful in the production of industrial catalysts.展开更多
A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology an...A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology and photoluminescence properties were measured by powder X-ray diffraction,scanning electron microscope and fluorescence spectrometer,respectively.The results show that uniform spherical microcrystals with diameters in the range of 2–4μm are obtained.And the phase and morphology of samples are not significantly changed by doping rare earth(RE^(3+))ions.Under the excitation wavelength of 356 and 365 nm,the samples BaWO 4:0.03Dy^(3+),yTm^(3+)can emit cold white light.In order to lower the correlated color temperature(CCT)to get a warm white light,the Eu^(3+)ions were doped into BaWO 4:0.03Dy^(3+),0.01Tm^(3+).Especially,under the excitation of 365 nm,BaWO 4:0.03Dy^(3+),0.01Tm^(3+),0.03Eu^(3+)phosphor shew a bright warm white light with color coordi-nate of(0.4013,0.3629)and CCT of 3288 K.Moreover,in the BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors,the energy transfer mechanism among Dy^(3+),Tm^(3+)and Eu^(3+)ions have been discussed and the change of electron structures have been calculated by first-principles calculations.The results shew that the uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors could be favorable candidates in warm white LEDs.展开更多
基金financially supported by the National Natural Science Foundation of China(21875265,22293015,22121002)。
文摘Phenol in waste water threatens human health and is difficultly to be decomposed by nature.Efficient degradation of high-loaded phenol in water under mild condition is still a great challenge.Herein,ionic liquids with tungstate anion were designed and prepared.It was found that dodecyltrimethylammonium tungstate could catalyzed degradation of phenol into gases and water thoroughly at 323 k in 8 h.Tungstate anion revealed good catalytic oxidative activity and long carbon chain group connecting with cation of ionic liquids enriched phenol around catalysts,which induced the complete degradation of phenol at mild conditions.Increasing the amounts of hydrogen peroxide benefited to the total degradation of phenol.In addition,the ionic liquid could be reused for its excellent thermal stability.Our work provided a different strategy to treat waste water containing phenol efficiently.
基金support of NSFC 51702284Fundamental Research Funds for the Central Universities (112109*172210171)+2 种基金the Startup Foundation for Hundred-Talent Program of Zhejiang University (112100-193820101/001/022)support of the NSFC 21501138the Science Research Foundation of Wuhan Institute of Technology (K201513)
文摘Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.
基金Supported by the Research Foundation of Akdeniz University, Turkey
文摘AIM: To evaluate the effect of sodium tungstate on visual evoked potentials(VEPs) in diabetic rats.· METHODS: Wistar rats were randomly divided into three groups as normal control, diabetic control and diabetic rats treated with sodium tungstate. Diabetes was induced by single intraperitoneal injection of streptozotocin(50 mg/kg). Sodium tungstate [40 mg/(kg·d)]was administered for 12 wk and then VEPs were recorded.Additionally, thiobarbituric acid reactive substance(TBARS) levels were measured in brain tissues.·RESULTS: The latencies of P1, N1, P2, N2 and P3 waves were significantly prolonged in diabetic rats compared with control group. Diabetes mellitus caused an increase in the lipid peroxidation process that was accompanied by changes in VEPs. However, prolonged latencies of VEPs for all components returned to control levels in sodium tungstate-treated group. The treatment of sodium tungstate significantly decreased brain TBARS levels and depleted the prolonged latencies of VEP components compared with diabetic control group.· CONCLUSION: Sodium tungstate shows protective effects on visual pathway in diabetic rats, and it can be worthy of further study for potential use.
文摘An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1 (C36H24 CuN6O19W6, Mr = 2011.20) was hydrothermally synthesized and characterized by single- crystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005(11), b = 11.2585(11), c = 20.2867(15) , β = 102.177(2)o, V = 4264.4 3, μ(MoKa) = 16.691 mm–1, Dc = 3.133 g/cm3, Z = 4, F(000) = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with I > 2σ(I). The result of structure determination shows that the crystal structure is constructed from [W6O19]2– cluster anions and [Cu(phen)3]2+ complex fragments, which are held together into a three-dimen- sional network through hydrogen-bonding interactions.
文摘The expanded industrial experiments were conducted with practical industfial liquor to separate free alkali from sodium tungstate solution by electrolysis with canon-exchange membrane. Experimental results show that on the condition that the temperature is 50-55℃ and the current density is 1000 A/m2, the single electrolysis cell is operated stably and 80% free-alkali in mass fraction is separated from the anode feed liquor of sodium tungstate, with electric ef- ficiency up to more than 88% and the unit energy consumption E lower than 1900 kWh/t; while three electfolysis cells in series are operated, under the condition that the temperature is 60-65 ℃ and the current density is 1000 A/m2, the elec- tric efficiency can reach higher than 88% and the unit energy consumption E can be lower than 2250 kWh/t.
文摘Xiao Liansheng Wang Wei Zhang Qixiu Gong Bofan Cao Jiashu (Department of Metallurgical Science and Engineering, Central South University of Technology, Changsha 410083, China) Abstrac By measuring the electrode polarization curves of many kinds of materials and life spans of electrodes through intensifying electrolysis in the process, the appropriate electrode materials for different stages of electrolysis of sodium tungstate solution with membrane have been selected The effects of the electrodes with different shapes on electrolysis have been investigated. The result shows that network electrode is more suitable to electrolysis of sodium tungstate solution.
文摘The crystal structure of lead tungstate (PbWO4) can be regarded as ordered combination of the tungsten oxide tetrahedrons (WO4) and lead ions (Pb2+). According to the growth unit model, the growth units of lead tungstate are the aggregations of the tungsten oxide tetrahedrons and lead cations with various geometry configurations. It is suggested that the favorable growth units of lead tungstate crystal are pyramidal, tetragonal prism and quadrangular units corresponding to geometric orientations of the simple forms of the crystal. Under low restricted growth conditions, the growth form of lead tungstate crystallites is the aggregation of the geometric configurations of these favorable growth units. The above conclusions are completely confirmed by the experiment on hydrothermal preparation of lead tungstate crystallites.
基金The authors acknowledge financial support from the National Natural Science Foundation of China(51402204 and 51772201)Thousand Young Talents Program,Jiangsu Specially-Appointed Professor Program,and a project funded by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘A hydrogel possessing interesting photochromic behaviors was developed by in situ ultraviolet(UV)irradiation-assisted polymerization of an aqueous solution of N-isopropylacrylamide monomer in the presence of cesium tungstate nanosheets.By this process,a hierarchical porous network structure was finely constructed while showing ultrahigh flexibility.More importantly,the newly prepared hydrogel retained the photochromic properties of the cesium tungstate nanosheets.The color transitions could be readily controlled by UV laser irradiation and were completely reversible via laser exposure or dark treatment.The nanocomposite hydrogel with its excellent photochromic properties and ultrahigh flexibility will have great applications in flexible photochromic devices.The synthetic procedure is simple and has promises to be extended to developing other hydrogels with various new functionalities.
基金the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020038)。
文摘The contamination of antibiotics in aqueous environment causes increasing concerns recently.Lightassisted activation of peroxydisulfate(PDS)has been demonstrated as an efficient technology for re moval of contamination in water.Herein,a hollow sphere of CuWO_(4)(h-CuWO_(4))was employed as a visible lightactivated photocatalyst for the activation of PDS,and following with high removal efficiency(98%)of antibiotic sulfamethoxazole(SMX).Under visible light irradiation,the degradation rate on hollow structures system is nearly 2 times higher than the traditional solid CuWO_(4) spheres.Furthermore,the underlying mechanism and detailed pathway of SMX degradation were proposed based on density functional theory(DFT)calculations and liquid chromatography-mass spectrometry(LC-MS).This work provides a new feasible way for advanced oxidation processes to remove antibiotics SMX in heterogeneous system,and open up new application possibilities of CuWO_(4)-based materials.
基金supported in part by Japan Science and Technology Agency Strategic International Collaborative Research Program(JST SICORP)Grant Number JPMJSC18H1,Japan.U.Rthe financial support by JICA IITH-FRIENDSHIP(D1956755)scholarship for suppoeting this study。
文摘This work presents the formation of butyl levulinate,a potential fuel additive,and an excellent renewable chemical obtained by the butanolysis of furfuryl alcohol(FAL)over a solid acid catalyst.The butanolysis of furfuryl alcohol reaction is a strong function of acidity for which tungstated zirconia(WO_(3)-ZrO_(2)),a robust solid acid catalyst,and a sulfonated carbon catalyst were employed to produce high yields of butyl levulinate targeting a lower initial molar ratio of butanol to FAL.A maximum of 28 mol%yield of butyl levulinate was obtained with tungstated zirconia catalyst.Easily prepared sulfonated carbon catalyst at high reaction temperatures facilitated the complete conversion of reaction intermediate,2-butoxymethylfuran(2-BMF)through which butyl levulinate was formed,and as high as 80 mol%of butyl levulinate yield was produced at an initial mole ratio of 8.5:1 of butanol to FAL.The better results of sulfonated carbon catalyst could be attributed to the presence of-SO3H,carboxylic acid,and phenolic OH groups on the carbon surface.
基金the National Key Research and Development Program of China(No.2020YFB1713500)the Opening Project of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials&Henan Key Laboratory of High-temperature Structural and Functional Materials,Henan University of Science and Technology(No.HKDNM2019013)+1 种基金the Student Research Training Plan of Henan University of Science and Technology(Nos.2021026 and 2021035)the Undergraduate Innovation and Entrepreneurship Training Program of Henan Province(No.S202110464005).
文摘Transition metal tungstate-based nanomaterials have become one of the research hotspots in electrochemistry due to their abundant natural resources,low costs,and environmental friendliness.Extensive studies have demonstrated their significant potentials for electrochemical applications,such as supercapacitors,Li-ion batteries,Na-ion batteries,electrochemical sensing,and electrocatalysis.Considering the rapidly growing research enthusiasm for this topic over the last several years,herein,a critical review of recent progress on the application of transition metal tungstates and their composites for electrochemical applications is summarized.The relationships between synthetic methods,nano/micro structures and electrochemical properties are systematically discussed.Finally,their promising prospects for future development are also proposed.It is anticipated that this review will inspire ongoing interest in rational designing and fabricating novel transition metal tungstate-based nanomaterials for high-performance electrochemical devices.
基金supported by Jilin Provincial Education Department (2009JYT15)Jilin Provincial Science and Technology Department (20090709)Changchun Science and Technology Bureau (2009110)
文摘The 10 at.% Er3+-doped KYb(WO4)2(KEr0.1Yb0.9(WO4)2) laser crystal with dimensions up to 25 mm×15 mm×10 mm was grown by the Kyropoulos method.The crystal structure was identified as β-KEr0.1Yb0.9(WO4)2 by XRD analysis.Through TG-DTA curves,the melting point and transition point of the crystal were determined to be 1058 and 1031 °C,respectively.Infrared spectrum and Raman spectrum were measured,and the vibration frequencies of infrared and Raman active modes for the crystal were assigned.The absorption cross section is 3.1×10-20 cm2 at chief peak of 981 nm with the absorption line width of 26 nm.Based on the Judd-Ofelt theory,the intensity parameters ?λ(λ=2,4,6) calculated were:?2=16.34×10-20 cm2,?4=4.18×10-20 cm2,and ?6=1.26×10-20 cm2.There was a strong emission peak near 1533 nm and the emission line width at the main peak at 1533 nm run up to 55 nm with the emission cross section of 3.47×10-20 cm2 .These optical parameters indicated the potential of this crystal used as an excellent laser material for 1540 nm nearby human-eye safe.
文摘Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and non-activated aro-matic compounds. The reactions were conducted under solvent-free conditions, which afforded good to excellent yields. The observed reaction times in MW assisted conditions are in the range of only few minutes.
文摘Whereas the light yield of PWO crystal can be significantly improved by doping with either of F- and Sb3+, effects of heavily co-doping with by F-+Sb3+, F-+Ca2+, and F-+Ca2++Sb3+, respectively, on the properties of PWO scintillation crystals, including optical transmission, luminescence and light yield were studied. The result indicates that co-doping with three dopants, F-+Ca2++Sb3+, is a more effective measure than doping with single dopant F- for the improvement of scintillation properties of PWO crystals, including light yield.
文摘The crystals of NaLn（WO4）<sub>2</sub>（Ln=La,Pr,Nd）are grown from a melt of LiCl-Na<sub>2</sub>WO<sub>4</sub> flux by slowcooling method.The chemical analysis data show that the crystals are NaLa（WO<sub>4</sub>）<sub>2</sub>,NaPr（WO4）<sub>2</sub> andNaNd（WO<sub>4</sub>）<sub>2</sub> respectively.The structures of the crystals are ascertained that they belong to scheelite structureof the tetragonal system with a space group of 14<sub>1</sub>/a.The lattice parameters of the crystals have beencalculated.It is found that the cell volume of NaLn（WO<sub>4</sub>）<sub>2</sub> crystals decrease with a decrease of Ln<sup>3+</sup>radius.The bond distances and their angles in NaLa（WO<sub>4</sub>）<sub>2</sub> and NaNd（WO<sub>4</sub>）<sub>2</sub> are given.It is found that inaccordance with the decrease of ionic radii of Ln<sup>3+</sup>due to increase of atomic number,the bond distances betweenLn-O,Ln-Ln and W-O decrease regularly.The infrared spectra of NaLn（WO<sub>4</sub>）<sub>2</sub> are measured.Thetetrahedra characteristic absorptions of WO<sub>4</sub><sup>2-</sup>are shown.The sensitization of host lattice is observed from theexcitation and fluorescent spectra of NaLa（WO<sub>4</sub>）<sub>2</sub> and NaPr（WO<sub>4</sub>）<sub>2</sub>.
基金financial support from the National Natural Science Foundation of P. R. China (21103049)
文摘The present paper reports new results regarding the addition of pseudo-boehmite as a binder during the synthesis of shaped Pt/WO_(3)-ZrO_(2)-Al_(2)O_(3) (PtWZA) catalysts. Binder shaping can noticeably influence not only the structure and acidity of catalyst and improve its catalytic performance with regard to n-heptane isomerization, but the mechanical strength of the catalyst. A suitable binder content can improve the isomerization activity or selectivity by changing the acidity of PtWZA. The influence of the binder content depends on the WO_(3) content of the catalyst. PtWZA catalysts that contain 5%-15% binder on a dry basis exhibit favorable isomerization performance that depends on WO_(3) content. Suitable catalysts include Pt20WZ5A and Pt30WZ15A, which provide conversions of approximately 80%-90% and a selectivity of 90%. These new findings enrich researcher knowledge of the effect of the binder on the catalyst shaping process and are useful in the production of industrial catalysts.
基金This work was supported by Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology and photoluminescence properties were measured by powder X-ray diffraction,scanning electron microscope and fluorescence spectrometer,respectively.The results show that uniform spherical microcrystals with diameters in the range of 2–4μm are obtained.And the phase and morphology of samples are not significantly changed by doping rare earth(RE^(3+))ions.Under the excitation wavelength of 356 and 365 nm,the samples BaWO 4:0.03Dy^(3+),yTm^(3+)can emit cold white light.In order to lower the correlated color temperature(CCT)to get a warm white light,the Eu^(3+)ions were doped into BaWO 4:0.03Dy^(3+),0.01Tm^(3+).Especially,under the excitation of 365 nm,BaWO 4:0.03Dy^(3+),0.01Tm^(3+),0.03Eu^(3+)phosphor shew a bright warm white light with color coordi-nate of(0.4013,0.3629)and CCT of 3288 K.Moreover,in the BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors,the energy transfer mechanism among Dy^(3+),Tm^(3+)and Eu^(3+)ions have been discussed and the change of electron structures have been calculated by first-principles calculations.The results shew that the uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors could be favorable candidates in warm white LEDs.
