The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58...The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58) were discussed.Pure β-W was obtained from oxide WO_(2.90),while there appears small amount of WO_2 during the reduction of W_(20)O_(58) to β-W.展开更多
The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to...The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to x-W was also studied in both hydrogen and nitrogen.The forming condition of β-W from WO_2 was discussed.Finally.a complete schematic diagram of reduction of tungsten oxides was given in this paper.展开更多
Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power...Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power transmission, and report on the realization of a heterojunction formed between WO2 and WO3 in a fine-wire having a diameter on the micrometer scale. Using a laser beam of 514.5 nm as a signal source, the WO2-WO3 heterojunction yields a maximum output power of up to 37.4 pico watt per heterojunction. Fast responses (less than a second) of both photovoltaic voltage and current are also observed. In addition, we demonstrate that it is a simple and effective way to adapt a commercial Raman spectrometer for the combined functions of fabrication, material characterization and photovottaic measurement of an optical signal coupler and optical power transmitter based on a fine-wire. Our results show an attractive perspective of developing nanowire or fine-wire elements for coupling optical signals into and for powering a nanoelectronic or nano-optoelectronic integrated circuit that works under the condition of preventing it from directly electrically connecting with the optical coupler.展开更多
Benzene series as highly toxic gases have inevitably entered human life and produce great threat to human health and ecological environment,and thus it is distinctly meaningful to monitor benzene series with quickly,r...Benzene series as highly toxic gases have inevitably entered human life and produce great threat to human health and ecological environment,and thus it is distinctly meaningful to monitor benzene series with quickly,real-time and efficient technique.Herein,novel sulfur-doped mesoporous WO_(3)materials were synthesized via classical in-situ solvent evaporation induced co-assembly strategy combined with doping engineering,which possessed highly crystallized frameworks,high specific surface area(40.9–63.8 m^(2)/g)and uniform pore size(~18 nm).Benefitting from abundant oxygen vacancy and defects via S-doping,the tailored mesoporous S/m WO_(3)exhibited excellent benzene sensing performance,including high sensitivity(50 ppm vs.48),low detection limit(ca.500 ppb),outstanding selectivity and favorable stability.In addition,the reduction of band gap resulted from S-doping promotes the carrier migration in the sensing materials and the reaction at the gas–solid sensing interfaces.It provides brand-new approach to design sensitive materials with multiple reaction sites.展开更多
Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides...Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological applications.With a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric counterparts.This review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related devices.Finally,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.展开更多
Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current st...Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.展开更多
We presented a strategy to prepare spherical tungsten powder by the combination of hydrothermal method and H2reduction process.In hydrothermal process,the micelle of tetraethylammonium bromide(TEAB)act as spherical te...We presented a strategy to prepare spherical tungsten powder by the combination of hydrothermal method and H2reduction process.In hydrothermal process,the micelle of tetraethylammonium bromide(TEAB)act as spherical templates for the deposition of tungsten oxide,whereas the excessive TEAB inhibit the formation of spherical tungsten oxide due to the dense molecular layer of TEAB on the tungsten oxide particles.Citric acid(CA)can control the formation rate and structure of the tungsten oxide when its concentration is more than 0.2 mol/L,because of its ability to coordinate with tungsten atoms.The synergistic effect of TEAB and CA facilitates the formation of spherical tungsten oxide with nanorod crown.After being treated by H_(2)at 600 and 650℃,the tungsten oxide particles are reduced to tungsten particles,which maintain the spherical structure of tungsten oxide and have porous structure.展开更多
Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungs...Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide(WO2.72)as the raw material,a fluidized bed as the reactor,and CO as the carbonization gas.The relationship between particle sizes and reaction temperatures,residence times,atmospheres has been investigated systematically.In addition,the physical–chemical indexes(such as residual oxygen,total carbon and free carbon)of the products were measured.The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950°C.As the residence time increased,the particle size decreased gradually,and then increased due to slight sintering.The introduction of hydrogen reduced the carbonization rate,and is not beneficial to obtaining nano-sized WC.Products that satisfy the standard were obtained when WO2.72 reacted with CO at 850°C,900°C and 950°C for 3.0 h,2.5 h and 2.0 h,respectively.The particle sizes of the three samples calculated from the specific surface area were 46.4 nm,53.2 nm and 52.1 nm,respectively.展开更多
Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost,high safety and eco-friendliness.However,the narrow operating potential window of aqueous electrolyte and the lack of ...Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost,high safety and eco-friendliness.However,the narrow operating potential window of aqueous electrolyte and the lack of suitable negative electrode materials seriously hinder its future applications.Here,we explore high concentrated lithium acetate with high ionic conductivity of 65.5 mS cm−1 as a green“water-in-salt”electrolyte,providing wide voltage window up to 2.8 V.It facilitates the reversible function of niobium tungsten oxide,Nb18W16O93,that otherwise only operations in organic electrolytes previously.The Nb18W16O93 with lithium-ion intercalation pseudocapacitive behavior exhibits excellent rate performance,high areal capacity,and ultra-long cycling stability.An aqueous lithium-ion hybrid capacitor is developed by using Nb18W16O93 as negative electrode combined with graphene as positive electrode in lithium acetate-based“water-in-salt”electrolyte,delivering a high energy density of 41.9 W kg−1,high power density of 20,000 W kg−1 and unexceptionable stability of 50,000 cycles.展开更多
Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour-solid (VS) mechanism.Tin powders are used to...Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour-solid (VS) mechanism.Tin powders are used to control oxygen concentration in the furnace,thereby assisting the growth of the tungsten oxide nanowires.The grown tungsten oxide nanowires are determined to be of crystalline W18O49. I-V curves are measured by an in situ transmission electron microscope (TEM) to investigate the electrical properties of the nanowires.All of the I-V curves observed are symmetric,which reveals that the tungsten oxide nanowires are semiconducting. Quantitative analyses of the experimental I-V curves by using a metal semiconductor-metal (MSM) model give some intrinsic parameters of the tungsten oxide nanowires,such as the carrier concentration,the carrier mobility and the conductivity.展开更多
It is usually difficult to remove dibenzothiophenes from diesel fuels by oxidation with molecular oxygen as an oxidant.In the study,tungsten oxide was supported on magnetic mesoporous silica by calcination to form a m...It is usually difficult to remove dibenzothiophenes from diesel fuels by oxidation with molecular oxygen as an oxidant.In the study,tungsten oxide was supported on magnetic mesoporous silica by calcination to form a magnetically separable catalyst for oxidative desulfurization of diesel fuel.By tuning different calcining temperatures,the catalyst calcined at 500℃showed a high catalytic activity with molecular oxygen as the oxidant.Under optimal reaction conditions,the sulfur removal of DBT reached 99.9%at 120℃after 8 h.Furthermore,the removals of 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene could also get up to 98.2%and 92.3%under the same conditions.The reaction mechanism was explored by selective quenching experiments and FT-IR spectra.展开更多
Owing to the increasingly serious environmental issues caused by the sulfur burnt in fuel, desulfurization has become an important topic. In this work, an amphiphilic oxygen-defective tungsten oxide was synthesized by...Owing to the increasingly serious environmental issues caused by the sulfur burnt in fuel, desulfurization has become an important topic. In this work, an amphiphilic oxygen-defective tungsten oxide was synthesized by a colloidal chemistry method. The amphiphilic property and oxygen defects were well characterized, and the structure of the oxygen-defective tungsten oxide catalyst was investigated. In addition, the catalyst was employed in oxidative desulfurization system of fuel,and deep desulfurization was achieved. It was found that the very high oxidative desulfurization performance of oxygendefective tungsten oxide catalyst resulted from both the amphiphilic property and oxygen defects. This work can provide a strategy for preparation of highly active metal oxide catalysts with oxygen defects in oxidative desulfurization reaction of fuel.展开更多
Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements...Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements indicate that the films annealed below 300℃ were amorphous, while the films annealed at 400 ℃ were mixed crystalline with hexagonal and triclinic phases of WO3. It was observed that the crystallization of the annealed films becomes more and more distinct with an increase in the annealing temperature. At 400 ℃, nanorod-like structures were observed on the film surface when the annealing time was increased from 60 min to 180 min. The presence of W=O stretching, W-O-W stretching, W-O-W bending and various lattice vibration modes were observed in Raman measurements. The optical absorption behaviors of the films in the range of 450-800 nm are very different with changing annealing temperatures from the room temperature to 400 ℃. After annealing at 400 ℃, the film becomes almost transparent. Increasing annealing time at 400 ℃ can lead to a small blue shift of the optical gap of the film.展开更多
A novel three-dimensional(3D) hierarchical structure and a roughly oriented one-dimensional(1D) nanowire of WO3 are selectively prepared on an alumina substrate by an induced hydrothermal growth method.Each hierar...A novel three-dimensional(3D) hierarchical structure and a roughly oriented one-dimensional(1D) nanowire of WO3 are selectively prepared on an alumina substrate by an induced hydrothermal growth method.Each hierarchical structure is constructed hydrothermally through bilateral inductive growth of WO3 nanowire arrays from a nanosheet preformed on the substrate.Only roughly oriented 1D WO3 nanowire can be obtained from a spherical induction layer.The analyses show that as-prepared 1D nanowire and 3D hierarchical structures exhibit monoclinic and hexagonal phases of WO3,respectively.The gas-sensing properties of the nanowires and the hierarchical structure of WO_3,which include the variations of their resistances and response times when exposed to NO2,are investigated at temperatures ranging from room temperature(20 ℃) to 250 ℃ over 0.015 ppm-5 ppm NO2.The hierarchical WO3 behaves as a p-type semiconductor at room temperature,and shows p-to-n response characteristic reversal with the increase of temperature.Meanwhile,unlike the1 D nanowire,the hierarchical WO3 exhibits an excellent response characteristic and very good reversibility and selectivity to NO2 gas at room temperature due to its unique microstructure.Especially,it is found that the hierarchical VO3-based sensor is capable of detecting NO2 at a ppb level with ultrashort response time shorter than 5 s,indicating the potential of this material in developing a highly sensitive gas sensor with a low power consumption.展开更多
Since the work of Penrose and Hameroff the possibility is discussed that the location of human memory and consciousness could be connected with tubulin microtubules. If one would use superionic nano-materials rolled u...Since the work of Penrose and Hameroff the possibility is discussed that the location of human memory and consciousness could be connected with tubulin microtubules. If one would use superionic nano-materials rolled up to microtubules with an electrolyte inside the formed channels mediating fast ionic exchange of protons respectively lithium ions, it seems to be possible to write into such materials whole image arrays (pictures) under the action of the complex electromagnetic spectrum that composes these images. The same material and architecture may be recommended for super-computers. Especially microtubules with a protofilament number of 13 are the most important to note. We connected such microtubules before with Fibonacci nets composed of 13 sub-cells that were helically rolled up to deliver suitable channels. Our recent Fibonacci analysis of Wadsley-Roth shear phases such as niobium tungsten oxide , exhibiting channels for ultra-fast lithium-ion diffusion, suggests to use these materials, besides super-battery main application, in form of nanorods or microtubules as effectively working superionic memory devices for computers that work ultra-fast with the complex effectiveness of human brains. Finally, we pose the question, whether dark matter, ever connected with ultrafast movement of ordinary matter, may be responsible for synchronization between interactions of human brains and consciousness.展开更多
There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyro...There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyrovsky step).Hybrid amorphous electrocatalysts are highly desirable for efficient hydrogen evolution from water-alkali electrolyzers due to the bifunctionality for the different elementary steps of HER and optimal interactions with water molecules and the reactive hydrogen intermediates(Had).Herein,the synthesis of amorphous hybrid ultrathin(tungsten oxide/nickel hydroxide)hydrate(a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O)nanosheets on nickel foam(NF)for efficient alkaline HER is described.The structural and composition features of a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O are characterized in detailed.The resulting a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O/NF electrocatalyst with the synergistic effect of both hybrid components for the HER elementary steps shows greatly improved the activity and durability for the HER with a low overpotential of-41 and-163 mV at-10 and-500 mA·cm^(-2),respectively,a Tafel slope as low as-72.9 mV·dec^(-1),and long-term stability of continuous electrolysis for at least 150 h accompanying by inappreciable overpotential change in 1 M KOH.In the hybrid a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O,Ni(OH)_(2) and WO_(3) moieties are separately responsible for accelerating dissociative adsorption of water and weakening Had adsorption strength,which is beneficial to the improvement of the alkaline HER activity.展开更多
Ruthenium(Ru)has been recognized as a prospective candidate to substitute platinum catalysts in water-splitting-based hydrogen production.However,minimizing the Ru contents,optimizing the water dissociation energy of ...Ruthenium(Ru)has been recognized as a prospective candidate to substitute platinum catalysts in water-splitting-based hydrogen production.However,minimizing the Ru contents,optimizing the water dissociation energy of Ru sites,and enhancing the long-term stability are extremely required,but still face a great challenge.Here,we report on creating tungsten oxide-anchored Ru clusters(Ru-WO_(x))with electron-rich and anti-corrosive microenvironments for efficient and robust seawater splitting.Benefiting from the abundant oxygen vacancy structure in tungsten oxide support,the Ru-WO_(x)exhibits strong Ru-O and Ru-W bonds at the interface.Our study elucidates that the strong Ru-O bonds in Ru-WO_(x)may accelerate the water dissociation kinetics,and the Ru-W bonds will lead to the strong metal-support interaction and electrons transfer fromWto Ru.The optimal Ru-WO_(x)catalysts exhibit a low overpotential of 29 and 218mVat the current density of 10 mA cm^(−2) in alkaline and seawater media,respectively.The outstanding long-term stability discloses that the Ru-WO_(x)catalysts own efficient corrosion resistance in seawater electrolysis.We believe that thiswork offers new insights into the essential roles of electron-rich and anti-corrosivemicroenvironments in Ru-based catalysts and provide a new pathway to design efficient and robust cathodes for seawater splitting.展开更多
Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an en...Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.展开更多
Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission...Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption--desorption. Both anatase TiO2 and orthorhombic WO3 formed in the nanocomposites, along with a highly disordered overlay of individual graphene nanosheets. Polyhedral and spherical TiO/and WO3 nanoparticles of uniform size 10-30 nm were densely anchored to the graphene sheets. The maximum specific surface area of the products was 144.59 m2·g^-1. The products showed clear abilities for the removal of Rhodamine B in the absence of illumination. Furthermore, the adsorption activity of the products exhibited only a slight decrease after three successive cycles. The results demonstrate that the ternary nanocomposites could be used as a high-efficiency adsorbent for the removal of environmental contaminants.展开更多
Effect of reaction temperature and pressure on the metathesis reaction between ethene and 2-butene to propene was studied on the WO3/γ-Al2O3-HY catalyst. The activity is found to increase with elevated temperature an...Effect of reaction temperature and pressure on the metathesis reaction between ethene and 2-butene to propene was studied on the WO3/γ-Al2O3-HY catalyst. The activity is found to increase with elevated temperature and reaches a plateau at 150-240 ℃. After that, the activity undergoes a remarkable decrement at too high temperature. The effect of temperature is elucidated by the oxidation state of tungsten species. The evaluation results also indicate that the stability is dependent on this reaction parameter. Medium pressure (0.5-0.8 MPa) is favorable for stability, while atmospheric pressure or too high pressure (〉1.0 MPa) deteriorates the stability. For explanation, UV Vis, FT-IR, O2-TPO, and TG techniques are used to characterize the spent catalysts.展开更多
文摘The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58) were discussed.Pure β-W was obtained from oxide WO_(2.90),while there appears small amount of WO_2 during the reduction of W_(20)O_(58) to β-W.
文摘The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to x-W was also studied in both hydrogen and nitrogen.The forming condition of β-W from WO_2 was discussed.Finally.a complete schematic diagram of reduction of tungsten oxides was given in this paper.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. U0634002,50725206 and 50672135)the National Basic Research Program of China (Grant Nos. 2003CB314701,2007CB935501 and 2008AA03A314)the Department of Information Industry of Guangdong Province,China
文摘Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power transmission, and report on the realization of a heterojunction formed between WO2 and WO3 in a fine-wire having a diameter on the micrometer scale. Using a laser beam of 514.5 nm as a signal source, the WO2-WO3 heterojunction yields a maximum output power of up to 37.4 pico watt per heterojunction. Fast responses (less than a second) of both photovoltaic voltage and current are also observed. In addition, we demonstrate that it is a simple and effective way to adapt a commercial Raman spectrometer for the combined functions of fabrication, material characterization and photovottaic measurement of an optical signal coupler and optical power transmitter based on a fine-wire. Our results show an attractive perspective of developing nanowire or fine-wire elements for coupling optical signals into and for powering a nanoelectronic or nano-optoelectronic integrated circuit that works under the condition of preventing it from directly electrically connecting with the optical coupler.
基金supported by the National Natural Science Foundation of China(Nos.22125501,U22A20152,22105043,52225204,52173233)Key Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.20JC1415300)+1 种基金the state key laboratory of Transducer Technology of China(No.SKT2207)the Fundamental Research Funds for the Central Universities(No.20720220010)。
文摘Benzene series as highly toxic gases have inevitably entered human life and produce great threat to human health and ecological environment,and thus it is distinctly meaningful to monitor benzene series with quickly,real-time and efficient technique.Herein,novel sulfur-doped mesoporous WO_(3)materials were synthesized via classical in-situ solvent evaporation induced co-assembly strategy combined with doping engineering,which possessed highly crystallized frameworks,high specific surface area(40.9–63.8 m^(2)/g)and uniform pore size(~18 nm).Benefitting from abundant oxygen vacancy and defects via S-doping,the tailored mesoporous S/m WO_(3)exhibited excellent benzene sensing performance,including high sensitivity(50 ppm vs.48),low detection limit(ca.500 ppb),outstanding selectivity and favorable stability.In addition,the reduction of band gap resulted from S-doping promotes the carrier migration in the sensing materials and the reaction at the gas–solid sensing interfaces.It provides brand-new approach to design sensitive materials with multiple reaction sites.
基金supported by the National Natural Science Foundation of China(No.61904080)the Macao Young Scholars Program of China(No.AM2020005)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110994).
文摘Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device properties.Controlling oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological applications.With a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric counterparts.This review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related devices.Finally,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.
基金supported by the National Natural Science Foundation of China(51902064)the Natural Science Foundation of Guangxi(2022GXNSFFA0350325)+2 种基金the Scientific and Technological Bases and Talents of Guangxi(Guike AD20159073)the special fund for“Guangxi Bagui Scholars”the“Guangxi HundredTalent Program”。
文摘Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.
基金Funded by the Key Program of Jiangxi Province on Development and Research(No.20203BBE53058)the Key Program of Ganzhou City on Development and Research(No.202101125003)。
文摘We presented a strategy to prepare spherical tungsten powder by the combination of hydrothermal method and H2reduction process.In hydrothermal process,the micelle of tetraethylammonium bromide(TEAB)act as spherical templates for the deposition of tungsten oxide,whereas the excessive TEAB inhibit the formation of spherical tungsten oxide due to the dense molecular layer of TEAB on the tungsten oxide particles.Citric acid(CA)can control the formation rate and structure of the tungsten oxide when its concentration is more than 0.2 mol/L,because of its ability to coordinate with tungsten atoms.The synergistic effect of TEAB and CA facilitates the formation of spherical tungsten oxide with nanorod crown.After being treated by H_(2)at 600 and 650℃,the tungsten oxide particles are reduced to tungsten particles,which maintain the spherical structure of tungsten oxide and have porous structure.
基金the financial support from the National Natural Science Foundation of China(Grant No.21878305)。
文摘Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide(WO2.72)as the raw material,a fluidized bed as the reactor,and CO as the carbonization gas.The relationship between particle sizes and reaction temperatures,residence times,atmospheres has been investigated systematically.In addition,the physical–chemical indexes(such as residual oxygen,total carbon and free carbon)of the products were measured.The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950°C.As the residence time increased,the particle size decreased gradually,and then increased due to slight sintering.The introduction of hydrogen reduced the carbonization rate,and is not beneficial to obtaining nano-sized WC.Products that satisfy the standard were obtained when WO2.72 reacted with CO at 850°C,900°C and 950°C for 3.0 h,2.5 h and 2.0 h,respectively.The particle sizes of the three samples calculated from the specific surface area were 46.4 nm,53.2 nm and 52.1 nm,respectively.
基金Shengyang Dong and Yi Wang contributed equally to this work.This work was supported by the National Natural Science Foundation of China(Nos.U1802256,51672128,51802154)the Key Research and Development Program in Jiangsu Province(BE2018122)+1 种基金Jiangsu Specially-Appointed Professors Program,the Fundamental Research Funds for the Central Universities(NE2016005)the Startup Foundation for Introducing Talent of NUIST(1441622001004).
文摘Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost,high safety and eco-friendliness.However,the narrow operating potential window of aqueous electrolyte and the lack of suitable negative electrode materials seriously hinder its future applications.Here,we explore high concentrated lithium acetate with high ionic conductivity of 65.5 mS cm−1 as a green“water-in-salt”electrolyte,providing wide voltage window up to 2.8 V.It facilitates the reversible function of niobium tungsten oxide,Nb18W16O93,that otherwise only operations in organic electrolytes previously.The Nb18W16O93 with lithium-ion intercalation pseudocapacitive behavior exhibits excellent rate performance,high areal capacity,and ultra-long cycling stability.An aqueous lithium-ion hybrid capacitor is developed by using Nb18W16O93 as negative electrode combined with graphene as positive electrode in lithium acetate-based“water-in-salt”electrolyte,delivering a high energy density of 41.9 W kg−1,high power density of 20,000 W kg−1 and unexceptionable stability of 50,000 cycles.
基金Project supported by the National Natural Science Foundation of China (Grant No 50671053)
文摘Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour-solid (VS) mechanism.Tin powders are used to control oxygen concentration in the furnace,thereby assisting the growth of the tungsten oxide nanowires.The grown tungsten oxide nanowires are determined to be of crystalline W18O49. I-V curves are measured by an in situ transmission electron microscope (TEM) to investigate the electrical properties of the nanowires.All of the I-V curves observed are symmetric,which reveals that the tungsten oxide nanowires are semiconducting. Quantitative analyses of the experimental I-V curves by using a metal semiconductor-metal (MSM) model give some intrinsic parameters of the tungsten oxide nanowires,such as the carrier concentration,the carrier mobility and the conductivity.
基金financially supported by the National Natural Science Foundation of China(Nos.21978119,21576122,and 21766007)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe support of the Jiangsu Government Scholarship for oversea studies。
文摘It is usually difficult to remove dibenzothiophenes from diesel fuels by oxidation with molecular oxygen as an oxidant.In the study,tungsten oxide was supported on magnetic mesoporous silica by calcination to form a magnetically separable catalyst for oxidative desulfurization of diesel fuel.By tuning different calcining temperatures,the catalyst calcined at 500℃showed a high catalytic activity with molecular oxygen as the oxidant.Under optimal reaction conditions,the sulfur removal of DBT reached 99.9%at 120℃after 8 h.Furthermore,the removals of 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene could also get up to 98.2%and 92.3%under the same conditions.The reaction mechanism was explored by selective quenching experiments and FT-IR spectra.
基金financial support by Students’ Platform for innovation and entrepreneurship training of Jiangsu Province (201810299008z)the National Nature Science Foundation of China (Nos. 21576122, 21722604, 21766007)+1 种基金Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, Hainan Normal University (20150376)the Natural Science Foundation of Jiangsu Provincial Department of Education (17KJA150002)
文摘Owing to the increasingly serious environmental issues caused by the sulfur burnt in fuel, desulfurization has become an important topic. In this work, an amphiphilic oxygen-defective tungsten oxide was synthesized by a colloidal chemistry method. The amphiphilic property and oxygen defects were well characterized, and the structure of the oxygen-defective tungsten oxide catalyst was investigated. In addition, the catalyst was employed in oxidative desulfurization system of fuel,and deep desulfurization was achieved. It was found that the very high oxidative desulfurization performance of oxygendefective tungsten oxide catalyst resulted from both the amphiphilic property and oxygen defects. This work can provide a strategy for preparation of highly active metal oxide catalysts with oxygen defects in oxidative desulfurization reaction of fuel.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant Nos.11104365 and 11104366)the Hubei Key Laboratory of Low Dimensional Optoelectronic Material and Devices,China(Grant No.13XKL02002)
文摘Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements indicate that the films annealed below 300℃ were amorphous, while the films annealed at 400 ℃ were mixed crystalline with hexagonal and triclinic phases of WO3. It was observed that the crystallization of the annealed films becomes more and more distinct with an increase in the annealing temperature. At 400 ℃, nanorod-like structures were observed on the film surface when the annealing time was increased from 60 min to 180 min. The presence of W=O stretching, W-O-W stretching, W-O-W bending and various lattice vibration modes were observed in Raman measurements. The optical absorption behaviors of the films in the range of 450-800 nm are very different with changing annealing temperatures from the room temperature to 400 ℃. After annealing at 400 ℃, the film becomes almost transparent. Increasing annealing time at 400 ℃ can lead to a small blue shift of the optical gap of the film.
基金supported by the National Natural Science Foundation of China(Grant Nos.61274074 and 61271070)the Natural Science Foundation of Tianjin,China(Grant No.11JCZDJC15300)
文摘A novel three-dimensional(3D) hierarchical structure and a roughly oriented one-dimensional(1D) nanowire of WO3 are selectively prepared on an alumina substrate by an induced hydrothermal growth method.Each hierarchical structure is constructed hydrothermally through bilateral inductive growth of WO3 nanowire arrays from a nanosheet preformed on the substrate.Only roughly oriented 1D WO3 nanowire can be obtained from a spherical induction layer.The analyses show that as-prepared 1D nanowire and 3D hierarchical structures exhibit monoclinic and hexagonal phases of WO3,respectively.The gas-sensing properties of the nanowires and the hierarchical structure of WO_3,which include the variations of their resistances and response times when exposed to NO2,are investigated at temperatures ranging from room temperature(20 ℃) to 250 ℃ over 0.015 ppm-5 ppm NO2.The hierarchical WO3 behaves as a p-type semiconductor at room temperature,and shows p-to-n response characteristic reversal with the increase of temperature.Meanwhile,unlike the1 D nanowire,the hierarchical WO3 exhibits an excellent response characteristic and very good reversibility and selectivity to NO2 gas at room temperature due to its unique microstructure.Especially,it is found that the hierarchical VO3-based sensor is capable of detecting NO2 at a ppb level with ultrashort response time shorter than 5 s,indicating the potential of this material in developing a highly sensitive gas sensor with a low power consumption.
文摘Since the work of Penrose and Hameroff the possibility is discussed that the location of human memory and consciousness could be connected with tubulin microtubules. If one would use superionic nano-materials rolled up to microtubules with an electrolyte inside the formed channels mediating fast ionic exchange of protons respectively lithium ions, it seems to be possible to write into such materials whole image arrays (pictures) under the action of the complex electromagnetic spectrum that composes these images. The same material and architecture may be recommended for super-computers. Especially microtubules with a protofilament number of 13 are the most important to note. We connected such microtubules before with Fibonacci nets composed of 13 sub-cells that were helically rolled up to deliver suitable channels. Our recent Fibonacci analysis of Wadsley-Roth shear phases such as niobium tungsten oxide , exhibiting channels for ultra-fast lithium-ion diffusion, suggests to use these materials, besides super-battery main application, in form of nanorods or microtubules as effectively working superionic memory devices for computers that work ultra-fast with the complex effectiveness of human brains. Finally, we pose the question, whether dark matter, ever connected with ultrafast movement of ordinary matter, may be responsible for synchronization between interactions of human brains and consciousness.
基金supported by the Six Talent Peaks Project in Jiangsu Province(No.JNHB-043)the Research Fund of State Key Laboratory of Materials-Oriented Chemical Engineering(No.ZK201713).
文摘There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyrovsky step).Hybrid amorphous electrocatalysts are highly desirable for efficient hydrogen evolution from water-alkali electrolyzers due to the bifunctionality for the different elementary steps of HER and optimal interactions with water molecules and the reactive hydrogen intermediates(Had).Herein,the synthesis of amorphous hybrid ultrathin(tungsten oxide/nickel hydroxide)hydrate(a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O)nanosheets on nickel foam(NF)for efficient alkaline HER is described.The structural and composition features of a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O are characterized in detailed.The resulting a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O/NF electrocatalyst with the synergistic effect of both hybrid components for the HER elementary steps shows greatly improved the activity and durability for the HER with a low overpotential of-41 and-163 mV at-10 and-500 mA·cm^(-2),respectively,a Tafel slope as low as-72.9 mV·dec^(-1),and long-term stability of continuous electrolysis for at least 150 h accompanying by inappreciable overpotential change in 1 M KOH.In the hybrid a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O,Ni(OH)_(2) and WO_(3) moieties are separately responsible for accelerating dissociative adsorption of water and weakening Had adsorption strength,which is beneficial to the improvement of the alkaline HER activity.
基金National Natural Science Foundation of China,Grant/Award Number:52273269Sichuan Science and Technology Program,Grant/Award Numbers:2023YFH0027,2023YFH0008+3 种基金Fundamental Research Funds for the Central UniversitiesState Key Laboratory of Polymer Materials Engineering,Grant/Award Numbers:sklpme2022-3-07,sklpme2021-4-02GRF,Grant/Award Number:CityU11308923The Basic Research Project from Shenzhen Science and Technology Innovation Committee,Grant/Award Number:JCYJ20210324134012034。
文摘Ruthenium(Ru)has been recognized as a prospective candidate to substitute platinum catalysts in water-splitting-based hydrogen production.However,minimizing the Ru contents,optimizing the water dissociation energy of Ru sites,and enhancing the long-term stability are extremely required,but still face a great challenge.Here,we report on creating tungsten oxide-anchored Ru clusters(Ru-WO_(x))with electron-rich and anti-corrosive microenvironments for efficient and robust seawater splitting.Benefiting from the abundant oxygen vacancy structure in tungsten oxide support,the Ru-WO_(x)exhibits strong Ru-O and Ru-W bonds at the interface.Our study elucidates that the strong Ru-O bonds in Ru-WO_(x)may accelerate the water dissociation kinetics,and the Ru-W bonds will lead to the strong metal-support interaction and electrons transfer fromWto Ru.The optimal Ru-WO_(x)catalysts exhibit a low overpotential of 29 and 218mVat the current density of 10 mA cm^(−2) in alkaline and seawater media,respectively.The outstanding long-term stability discloses that the Ru-WO_(x)catalysts own efficient corrosion resistance in seawater electrolysis.We believe that thiswork offers new insights into the essential roles of electron-rich and anti-corrosivemicroenvironments in Ru-based catalysts and provide a new pathway to design efficient and robust cathodes for seawater splitting.
基金financially supported by the National Natural Science Fundation of China(No.51125007)the National Basic Research Program(No.2012CB215500)
文摘Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.
基金financially supported by the National Natural Science Foundation of China (No. 41340037)the Science Foundation for Youth Scholars of State Oceanic Administration (No. 2012508)+2 种基金the Scientific Research Program of Shandong Province (No. 2013G0021701)the Natural Science Foundation of Shandong Province, China (No. ZR2011BL012 and ZR2012EMM015)the Scientific Research Program of Qingdao (No.11-2-4-3-15-jch)
文摘Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption--desorption. Both anatase TiO2 and orthorhombic WO3 formed in the nanocomposites, along with a highly disordered overlay of individual graphene nanosheets. Polyhedral and spherical TiO/and WO3 nanoparticles of uniform size 10-30 nm were densely anchored to the graphene sheets. The maximum specific surface area of the products was 144.59 m2·g^-1. The products showed clear abilities for the removal of Rhodamine B in the absence of illumination. Furthermore, the adsorption activity of the products exhibited only a slight decrease after three successive cycles. The results demonstrate that the ternary nanocomposites could be used as a high-efficiency adsorbent for the removal of environmental contaminants.
基金Financial support by National Natural Science Foundation of China (No. 20303019)National 973 Project of China (No.2003CB615802).
文摘Effect of reaction temperature and pressure on the metathesis reaction between ethene and 2-butene to propene was studied on the WO3/γ-Al2O3-HY catalyst. The activity is found to increase with elevated temperature and reaches a plateau at 150-240 ℃. After that, the activity undergoes a remarkable decrement at too high temperature. The effect of temperature is elucidated by the oxidation state of tungsten species. The evaluation results also indicate that the stability is dependent on this reaction parameter. Medium pressure (0.5-0.8 MPa) is favorable for stability, while atmospheric pressure or too high pressure (〉1.0 MPa) deteriorates the stability. For explanation, UV Vis, FT-IR, O2-TPO, and TG techniques are used to characterize the spent catalysts.