Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in t...Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO2 showed the highest activity and N2 selectivity at 225-375 ~C. The results of X-ray photo- electron spectroscopy, NH3-temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO2/H2O durability of Cu-V/TiO2 make it a candidate to be a NOx removal catalyst for stationary flue gas.展开更多
In recent years,photocatalytic technologies have been extensively studied and diffusely used in water splitting,decomposition of organic pollutants,reduction of carbon dioxide,etc.As a type of eye-catching semiconduct...In recent years,photocatalytic technologies have been extensively studied and diffusely used in water splitting,decomposition of organic pollutants,reduction of carbon dioxide,etc.As a type of eye-catching semiconductors,BiVO_(4),Bi_(2)WO_(6),and Bi_(2)MoO_(6) (denoted as BiaAOb)have become a hotspot in photocatalytic researches due to their crystal structure stability,high light quantum and electronic transmission efficiency,and outstanding energy utilization capacity.However,pristine BiaAOb(A=V,W,and Mo)possesses several drawbacks,such as low separation efficiency of photo-excited electron-hole pairs,low specific surface area,as well as the poor quantum utilization,which restrict their photocatalytic performance.Considerable efforts,such as nanostructure modification,surface engineering,and heterojunction/homojunction fabrication,have been conducted to solve these problems.This integrated review aims to sum up recent advances in current studies on fabrication of high efficiency BiaAOb photocatalysts to accelerate the developments of BiaAOb-based materials in the photocatalysis(PC)field.The current challenges and prospects of BiaAOb are emphasized which stretches the existing fundamental theories of PC as well as provide a promising strategy to fabricate high efficiency BiaAOb catalysts to control environmental pollution and assist the sustainable development of energy.展开更多
Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Antho...Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Anthocyanic Vacuolar Inclusions （AVIs）. Using Arabidopsis seedlings grown under anthocyanin-inductive conditions as a model to un- derstand how AVIs are formed, we show here that the accumulation of AVIs strongly correlates with the formation of cyanidin 3-glucoside （C3G） and derivatives. Arabidopsis mutants that fail to glycosylate anthocyanidins at the 5-0 position （Sgt mutant） accumulate AVIs in almost every epidermal cell of the cotyledons, as compared to wild-type seedlings, where only a small fraction of the cells show AVIs. A similar phenomenon is observed when seedlings are treated with vanadate. Highlighting a role for autophagy in the formation of the AVIs, we show that various mutants that interfere with the autophagic process （atg mutants） display lower numbers of AVIs, in addition to a reduced accumulation of anthocyanins. Interestingly, vanadate increases the numbers of AVIs in the atg mutants, suggesting that several pathways might participate in AVl formation. Taken together, our results suggest novel mechanisms for the formation of sub-vacuolar compartments capable of accumulating anthocyanin pigments.展开更多
A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate w...A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate was realized by ion-exchange reaction.The structure,morphology and composition of as-prepared LDH film were investigated by X-ray diffractometer,field-emission scanning electronic microscope and energy dispersive spectrometry.Results indicated that a uniform and compact LDH film was formed and the intercalation of Ce^(3+)and vanadate would change the crystal structure of LDHs.The results of the potentiodynamic polarization,electrochemical impedance spectra,hydrogen evolution and corrosion weight loss tests showed the Ce^(3+)and vanadate anions significantly improve the impedance of LDH film,and the active double-doped LDH film could effectively protect the magnesium substrate from corrosion.展开更多
Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain ...Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+.Here,we report on H11Al2V6O23.2@graphene(HAVO@G)with exceptionally large layer spacing of(001)plane(13.36?).The graphene-wrapped structure can keep the structure stable during discharge/charge process,thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte.While used as cathode for AZIBs,HAVO@G electrode delivers ideal rate performance(reversible capacity of 305.4,276.6,230.0,201.7,180.6 mAh g?1 at current densities between 1 and 10 A g?1).Remarkably,the electrode exhibits excellent and stable cycling stability even at a high loading mass of^15.7 mg cm?2,with an ideal reversible capacity of 131.7 mAh g?1 after 400 cycles at 2 A g?1.展开更多
Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniqu...Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.展开更多
Trivalent dysprosium(Dy) activated nanocrystalline yttrium vanadate(YVO) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrar...Trivalent dysprosium(Dy) activated nanocrystalline yttrium vanadate(YVO) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), optical absorption and photo luminescence(PL) techniques. The XRD patterns reveal the tetragonal crystalline phase. SEM images reveal that Dy doped YVOnanocrystals are agglomerated. EDAX confirms the formation of YVO:Dy. FTIR spectrum shows two strong absorption bands at 459 and 761 cm. Optical absorption spectrum showed the surface defects in the as-prepared samples. The PL emission spectrum shows two characteristic emission bands at 485 and 575 nm. The strong yellow emission peak at 575 nm is assigned to ~4 F→~6 Hhyper sensitive transition of Dyions, Study of CIE chromaticity diagram indicates the suitability of the phosphor for the development of yellow-green LEDs.展开更多
High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate ...High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate capability,and low initial coulombic efficiency(ICE)of anode materials.Herein,we report layered iron vanadate(Fe5V15O39(OH)9·9H2O)ultrathin nanosheets with a thickness of~2.2 nm(FeVO UNSs)as a novel anode for rapid and reversible sodium-ion storage.According to in situ synchrotron X-ray diffractions and electrochemical analysis,the storage mechanism of FeVO UNSs anode is Na+intercalation pseudocapacitance under a safe potential window.The FeVO UNSs anode delivers high ICE(93.86%),high reversible capacity(292 mAh g^−1),excellent cycling stability,and remarkable rate capability.Furthermore,a pseudocapacitor–battery hybrid SIC(PBH-SIC)consisting of pseudocapacitor-type FeVO UNSs anode and battery-type Na3(VO)2(PO4)2F cathode is assembled with the elimination of presodiation treatments.The PBH-SIC involves faradaic reaction on both cathode and anode materials,delivering a high energy density of 126 Wh kg^−1 at 91 W kg^−1,a high power density of 7.6 kW kg^−1 with an energy density of 43 Wh kg−1,and 9000 stable cycles.The tunable vanadate materials with high-performance Na+intercalation pseudocapacitance provide a direction for developing next-generation highenergy capacitors.展开更多
High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety is...High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety issues and low energy density.Here we hypothesize that a cobalt vanadate oxide,Co_(2)VO_(4),can be attractive anode material for fast-charging LIBs due to its high capacity(~1000 mAh g^(−1))and safe lithiation potential(~0.65 V vs.Li^(+)/Li).The Li+diffusion coefficient of Co2VO4 is evaluated by theoretical calculation to be as high as 3.15×10^(-10) cm^(2) s^(−1),proving Co_(2)VO_(4) a promising anode in fast-charging LIBs.A hexagonal porous Co2VO4 nanodisk(PCVO ND)structure is designed accordingly,featuring a high specific surface area of 74.57 m^(2) g^(−1) and numerous pores with a pore size of 14 nm.This unique structure succeeds in enhancing Li^(+) and electron transfer,leading to superior fast-charging performance than current commercial anodes.As a result,the PCVO ND shows a high initial reversible capacity of 911.0 mAh g^(−1) at 0.4 C,excellent fast-charging capacity(344.3 mAh g^(−1) at 10 C for 1000 cycles),outstanding long-term cycling stability(only 0.024% capacity loss per cycle at 10 C for 1000 cycles),confirming the commercial feasibility of PCVO ND in fast-charging LIBs.展开更多
This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on ox...This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on oxygen‐vacancy‐containing BiVO4.The morphology of the BiVO4is olive shaped,and it has a uniform size distribution.The BiVO4possesses a high oxygen vacancy density,and the resulting Ag nanoparticle‐BiVO4catalyst exhibits higher photocatalytic activity than BiVO4.The RhB degradation by the Ag nanoparticle‐BiVO4catalyst is99%after100min of simulated solar irradiation.BiVO4containing oxygen vacancies as a rationally designed support extends the catalyst response into the near‐infrared region,and facilitates the trapping and transfer of plasmonic hot electrons.The enhanced photocatalytic efficiency is attributed to charge transfer from the BiVO4to Ag nanoparticles,and surface plasmon resonance of the Ag nanoparticles.These insights into electron‐hole separation and charge transfer may arouse interest in solar‐driven wastewater treatment and water splitting.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadi...The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.展开更多
In this study, a potentially universal new strategy is reported for the large-scale, low-cost fabrication of visible-light-active highly ordered heteronanostructures based on the spontaneous photoelectric-field-enhanc...In this study, a potentially universal new strategy is reported for the large-scale, low-cost fabrication of visible-light-active highly ordered heteronanostructures based on the spontaneous photoelectric-field-enhancement effect inherent in pyramidal morphology. The hierarchical vertically oriented arrayed structures comprise an active molecular co-catalyst at the apex of a visible-light-active large band gap semiconductor for low-cost solar water splitting in a neutral aqueous medium without the use of a sacrificial agent.展开更多
Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide （y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40） photocatalysts were fabricated using the dodecylamine-assisted alcohol...Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide （y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40） photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-δS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m^2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi^5＋, Bi^3＋, V^5＋, V^3＋, Fe^3＋, and Fe^2＋ species in y wt.% FeOx/BiVO4-δS0.08. The 1.40 wt.% FeOx/BiVO4-δS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower baudgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-δS0.08.展开更多
We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and Y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxV...We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and Y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxVO4 crystallized in the tetragonal zircon type structure, belonging to the space group of I41/amd. The incorporation of a small amount of Zn to Ro.94Euo.06VO4 improved the emission characteristics. The emission intensities of the Gdo.88EUo.06Zno.06VO4 and Yo.9Euo.06Zno.04VO4 phosphors at 619 nm were 72% and 2 1% stronger than those of the Gdo,94Euo.06VO4 and Yo.94Euo.06VO4 phosphors, respectively. We demonstrated that the addi- tion of Zn to Ro.94Euo.06VO4 was quite effective for improving the photoluminescent properties.展开更多
基金supported by the National Natural Science Foundation of China (21303099)the National Basic Research Program of China(973 Program,2014CB660803)+1 种基金the Shanghai Municipal Education Commission(14ZZ097, B.3704713001)the Research Fund for Innovation Program of Shanghai University (K.10040713003)~~
文摘Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO2 showed the highest activity and N2 selectivity at 225-375 ~C. The results of X-ray photo- electron spectroscopy, NH3-temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO2/H2O durability of Cu-V/TiO2 make it a candidate to be a NOx removal catalyst for stationary flue gas.
基金financially supported by the National Natural Science Foundation of China(Nos.21271022,51972180,and 51572134)the Program for Scientific Research Innovation Team in Colleges and Universities of Jinan(No.2018GXRC006)the Key Research&Development Project of Shandong Province(No.2019GGX102070)。
文摘In recent years,photocatalytic technologies have been extensively studied and diffusely used in water splitting,decomposition of organic pollutants,reduction of carbon dioxide,etc.As a type of eye-catching semiconductors,BiVO_(4),Bi_(2)WO_(6),and Bi_(2)MoO_(6) (denoted as BiaAOb)have become a hotspot in photocatalytic researches due to their crystal structure stability,high light quantum and electronic transmission efficiency,and outstanding energy utilization capacity.However,pristine BiaAOb(A=V,W,and Mo)possesses several drawbacks,such as low separation efficiency of photo-excited electron-hole pairs,low specific surface area,as well as the poor quantum utilization,which restrict their photocatalytic performance.Considerable efforts,such as nanostructure modification,surface engineering,and heterojunction/homojunction fabrication,have been conducted to solve these problems.This integrated review aims to sum up recent advances in current studies on fabrication of high efficiency BiaAOb photocatalysts to accelerate the developments of BiaAOb-based materials in the photocatalysis(PC)field.The current challenges and prospects of BiaAOb are emphasized which stretches the existing fundamental theories of PC as well as provide a promising strategy to fabricate high efficiency BiaAOb catalysts to control environmental pollution and assist the sustainable development of energy.
文摘Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Anthocyanic Vacuolar Inclusions （AVIs）. Using Arabidopsis seedlings grown under anthocyanin-inductive conditions as a model to un- derstand how AVIs are formed, we show here that the accumulation of AVIs strongly correlates with the formation of cyanidin 3-glucoside （C3G） and derivatives. Arabidopsis mutants that fail to glycosylate anthocyanidins at the 5-0 position （Sgt mutant） accumulate AVIs in almost every epidermal cell of the cotyledons, as compared to wild-type seedlings, where only a small fraction of the cells show AVIs. A similar phenomenon is observed when seedlings are treated with vanadate. Highlighting a role for autophagy in the formation of the AVIs, we show that various mutants that interfere with the autophagic process （atg mutants） display lower numbers of AVIs, in addition to a reduced accumulation of anthocyanins. Interestingly, vanadate increases the numbers of AVIs in the atg mutants, suggesting that several pathways might participate in AVl formation. Taken together, our results suggest novel mechanisms for the formation of sub-vacuolar compartments capable of accumulating anthocyanin pigments.
基金financially supported by the National Natural Science Foundation of China(No.51971040)the Graduate Research and Innovation Foundation of Chongqing,China(No.CYS19002)+4 种基金the National Natural Science Foundation of China(Nos.51701029 and 51531002)the National Key Research and Development Program of China(No.2016YFB0301100)the China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)the Fundamental Research Funds for the Central Universities(No.2018CDGFCL005)。
文摘A doublely-doped layered double hydroxide(LDH)film was produced on an anodized magnesium alloy AZ31.The Ce-doped Mg-Al LDH film was prepared by in-situ hydrothermal treatment method,and the intercalation of vanadate was realized by ion-exchange reaction.The structure,morphology and composition of as-prepared LDH film were investigated by X-ray diffractometer,field-emission scanning electronic microscope and energy dispersive spectrometry.Results indicated that a uniform and compact LDH film was formed and the intercalation of Ce^(3+)and vanadate would change the crystal structure of LDHs.The results of the potentiodynamic polarization,electrochemical impedance spectra,hydrogen evolution and corrosion weight loss tests showed the Ce^(3+)and vanadate anions significantly improve the impedance of LDH film,and the active double-doped LDH film could effectively protect the magnesium substrate from corrosion.
基金supported by National Natural Science Foundation of China(Nos.51972346,51932011,51802356,and 51872334)Innovation-Driven Project of Central South University(No.2018CX004).
文摘Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+.Here,we report on H11Al2V6O23.2@graphene(HAVO@G)with exceptionally large layer spacing of(001)plane(13.36?).The graphene-wrapped structure can keep the structure stable during discharge/charge process,thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte.While used as cathode for AZIBs,HAVO@G electrode delivers ideal rate performance(reversible capacity of 305.4,276.6,230.0,201.7,180.6 mAh g?1 at current densities between 1 and 10 A g?1).Remarkably,the electrode exhibits excellent and stable cycling stability even at a high loading mass of^15.7 mg cm?2,with an ideal reversible capacity of 131.7 mAh g?1 after 400 cycles at 2 A g?1.
基金supported by the National Natural Science Foundation of China (No. 20973017, 21077007)the Creative Research Foundation of Beijing University of Technology (No. 00500054R4003, 005000543111501)+2 种基金the HiTech Research and Development Program (863)of China (No. 2009AA063201)the Funding Projectfor Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (No. PHR200907105, PHR201007105,PHR201107104)the Hong Kong Baptist University (FRG2/09-10/023)
文摘Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.
文摘Trivalent dysprosium(Dy) activated nanocrystalline yttrium vanadate(YVO) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), optical absorption and photo luminescence(PL) techniques. The XRD patterns reveal the tetragonal crystalline phase. SEM images reveal that Dy doped YVOnanocrystals are agglomerated. EDAX confirms the formation of YVO:Dy. FTIR spectrum shows two strong absorption bands at 459 and 761 cm. Optical absorption spectrum showed the surface defects in the as-prepared samples. The PL emission spectrum shows two characteristic emission bands at 485 and 575 nm. The strong yellow emission peak at 575 nm is assigned to ~4 F→~6 Hhyper sensitive transition of Dyions, Study of CIE chromaticity diagram indicates the suitability of the phosphor for the development of yellow-green LEDs.
基金This work was financially supported by the National Natural Science Foundation of China(No.22005256)the National Key R&D Program of China(Grant No.2016YFA0202600)the Natural Science Foundation of Fujian Province of China(No.2020J01034).
文摘High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate capability,and low initial coulombic efficiency(ICE)of anode materials.Herein,we report layered iron vanadate(Fe5V15O39(OH)9·9H2O)ultrathin nanosheets with a thickness of~2.2 nm(FeVO UNSs)as a novel anode for rapid and reversible sodium-ion storage.According to in situ synchrotron X-ray diffractions and electrochemical analysis,the storage mechanism of FeVO UNSs anode is Na+intercalation pseudocapacitance under a safe potential window.The FeVO UNSs anode delivers high ICE(93.86%),high reversible capacity(292 mAh g^−1),excellent cycling stability,and remarkable rate capability.Furthermore,a pseudocapacitor–battery hybrid SIC(PBH-SIC)consisting of pseudocapacitor-type FeVO UNSs anode and battery-type Na3(VO)2(PO4)2F cathode is assembled with the elimination of presodiation treatments.The PBH-SIC involves faradaic reaction on both cathode and anode materials,delivering a high energy density of 126 Wh kg^−1 at 91 W kg^−1,a high power density of 7.6 kW kg^−1 with an energy density of 43 Wh kg−1,and 9000 stable cycles.The tunable vanadate materials with high-performance Na+intercalation pseudocapacitance provide a direction for developing next-generation highenergy capacitors.
基金supported by the National Key Research and Development Project(2018YFE0124800)the National Nature Science Foundation of China(51702157,51873086,51673096).
文摘High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety issues and low energy density.Here we hypothesize that a cobalt vanadate oxide,Co_(2)VO_(4),can be attractive anode material for fast-charging LIBs due to its high capacity(~1000 mAh g^(−1))and safe lithiation potential(~0.65 V vs.Li^(+)/Li).The Li+diffusion coefficient of Co2VO4 is evaluated by theoretical calculation to be as high as 3.15×10^(-10) cm^(2) s^(−1),proving Co_(2)VO_(4) a promising anode in fast-charging LIBs.A hexagonal porous Co2VO4 nanodisk(PCVO ND)structure is designed accordingly,featuring a high specific surface area of 74.57 m^(2) g^(−1) and numerous pores with a pore size of 14 nm.This unique structure succeeds in enhancing Li^(+) and electron transfer,leading to superior fast-charging performance than current commercial anodes.As a result,the PCVO ND shows a high initial reversible capacity of 911.0 mAh g^(−1) at 0.4 C,excellent fast-charging capacity(344.3 mAh g^(−1) at 10 C for 1000 cycles),outstanding long-term cycling stability(only 0.024% capacity loss per cycle at 10 C for 1000 cycles),confirming the commercial feasibility of PCVO ND in fast-charging LIBs.
基金supported by the National Natural Science Foundation of China(21476033)~~
文摘This study investigates the photodegradation of the organic dye rhodamine B by Ag‐nanoparticlecontaining BiVO4catalysts under different irradiation conditions.The catalysts consist of Ag nanoparticles deposited on oxygen‐vacancy‐containing BiVO4.The morphology of the BiVO4is olive shaped,and it has a uniform size distribution.The BiVO4possesses a high oxygen vacancy density,and the resulting Ag nanoparticle‐BiVO4catalyst exhibits higher photocatalytic activity than BiVO4.The RhB degradation by the Ag nanoparticle‐BiVO4catalyst is99%after100min of simulated solar irradiation.BiVO4containing oxygen vacancies as a rationally designed support extends the catalyst response into the near‐infrared region,and facilitates the trapping and transfer of plasmonic hot electrons.The enhanced photocatalytic efficiency is attributed to charge transfer from the BiVO4to Ag nanoparticles,and surface plasmon resonance of the Ag nanoparticles.These insights into electron‐hole separation and charge transfer may arouse interest in solar‐driven wastewater treatment and water splitting.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51974369)the Postgraduate Research Innovation Project of Central South University,China(2019zzts244).
文摘The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.
文摘In this study, a potentially universal new strategy is reported for the large-scale, low-cost fabrication of visible-light-active highly ordered heteronanostructures based on the spontaneous photoelectric-field-enhancement effect inherent in pyramidal morphology. The hierarchical vertically oriented arrayed structures comprise an active molecular co-catalyst at the apex of a visible-light-active large band gap semiconductor for low-cost solar water splitting in a neutral aqueous medium without the use of a sacrificial agent.
基金supported by the National Natural Science Foundation of China(No.21077007)the Natural Science Foundation of Beijing Municipality(No.2102008)+3 种基金the Discipline and Postgraduate Education Foundation(No.PXM2013 014204 07 000261,005000542513551)the Creative Research Foundation of Beijing University of Technology(No.00500054R4003,005000543111501)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality(No.PHR201007105,PHR201107104)the Hong Kong Baptist University for financial support(No.FRG2/09-10/023)
文摘Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide （y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40） photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-δS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m^2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi^5＋, Bi^3＋, V^5＋, V^3＋, Fe^3＋, and Fe^2＋ species in y wt.% FeOx/BiVO4-δS0.08. The 1.40 wt.% FeOx/BiVO4-δS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower baudgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-δS0.08.
文摘We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and Y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxVO4 crystallized in the tetragonal zircon type structure, belonging to the space group of I41/amd. The incorporation of a small amount of Zn to Ro.94Euo.06VO4 improved the emission characteristics. The emission intensities of the Gdo.88EUo.06Zno.06VO4 and Yo.9Euo.06Zno.04VO4 phosphors at 619 nm were 72% and 2 1% stronger than those of the Gdo,94Euo.06VO4 and Yo.94Euo.06VO4 phosphors, respectively. We demonstrated that the addi- tion of Zn to Ro.94Euo.06VO4 was quite effective for improving the photoluminescent properties.
