It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxi...It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.展开更多
All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical applic...All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.展开更多
Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence q...Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence quantum yields(PLQY)restrict further applications.In this study,we synthesized Al^(3+),Er^(3+)-co-doped Gd_(3)Ga_(5)O_(12) garnets with multimode luminescence via a high-temperature solid-state method.Notably,the preferential substitution of Al^(3+)ion at octahedral-coordinated GaI sites significantly enhanced the charge density and electron transition probability,achieving a PLQY enhancement of the downshifting luminescence from 35.1%to 68.5%.Al^(3+)ion also influences electron relaxation during up-conversion luminescence,resulting in a color shift from red to yellow to green.Additionally,Al^(3+)incorporation increased the photoelectric conversion efficiency of light-emitting diodes from 2.9%to 6.3%and improved temperature sensing sensitivity from 2.7%to 5.1%K⁻1.This work provides new insights into the photophysical mechanisms and underscores the key role of Al^(3+)ion in optimizing the optical properties of garnet-based materials.展开更多
The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrog...The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrogen production from water splitting.In this work,M-MnO_(2)@TNTA composite electrodes were prepared by depositing various metal ion-doped manganese oxide nanoparticles on the titania nanotube array(TNTA)by successive ionic layer adsorption reaction(SILAR)method,and their HER and OER electrocatalytic performances were investigated in 1 M KOH.Results show that the CoFe-MnO_(2)@TNTA composite electrode prepared by simultaneous doping of Co^(3+)and Fe^(3+)in MnO_(2) exhibits optimal catalytic performance.Compared with MnO_(2)@TNTA without ion doping,the overpotentials of CoFe-MnO_(2)@TNTA at 10 mA cm^(-2)(η_(10))for HER and OER are reduced by 571 and 665 mV.In addition,the electrode perfor-mance can be significantly enhanced by increasing the test temperature,and the porous array structure enables CoFe-MnO_(2)@TNTA to exhibit better performance at high current densities.At 50℃,which is the common industrial electrolytic water temperature,the η_(10) of CoFe-MnO_(2)@TNTA for HER is almost equal to that of the Pt/C electrode.The η_(100) of CoFe-MnO_(2)@TNTA for HER is reduced by 35 mV compared with the Pt/C electrode.Moreover,η_(200) of CoFe-MnO_(2)@TNTA for OER is significantly lowered by 111 and 184 mV compared with IrO_(2) and RuO_(2) electrodes.Utilizing CoFe-MnO_(2)@TNTA as both the cathode and anode for overall water splitting,the electrolysis voltage is merely 2.33 V under the current density of 200 mA cm^(-2),much lower than that of IrO_(2)(+)||Pt/C(-)(2.68 V).The present work may provide a valuable reference for the development of self-supporting bifunctional electrodes suitable for high-current-density water splitting at industrial temperatures.展开更多
Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal env...Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal environmental impact.However,these materials suffer from poor rate capability and low-temperature performance owing to limited electronic and ionic conductivity,which restricts their practical applicability.Recent developments,such as coating material particles with carbon or a conductive polymer,crystal deformation through the doping of foreign metal ions,and the production of nanostructured materials,have significantly enhanced the electrochemical performances of these materials.The successful applications of polyanion-based materials,especially in lithium-ion batteries,have been extensively reported.This comprehensive review discusses the current progress in crystal deformation in polyanion-based cathode materials,including phosphates,fluorophosphates,pyrophosphates,borates,silicates,sulfates,fluorosilicates,and oxalates.Therefore,this review provides detailed discussions on their synthesis strategies,electrochemical performance,and the doping of various ions.展开更多
Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be exte...Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.展开更多
Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampe...Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampered by the poor charge carrier transport and high recombination.Herein,we develop a facile salt template-assisted interfacial polymerization strategy that insitu introduces alkali ions(Na+,K+)and nitrogen defects in CN(denoted as v-CN-KNa)to simultaneously promote charge separation and transportation and steer photoexcited holes and electrons to their oxidation and reduction sites.The photocatalyst exhibits an impressive photocatalytic H_(2) evolution rate of 8641.5μmol·g^(−1)·h^(−1)(33-fold higher than pristine CN)and also works readily in real seawater(10752.0μmol·g^(−1)·h^(−1))with a high apparent quantum efficiency up to 18.5%at 420 nm.In addition,we further demonstrate that the v-CN-KNa can simultaneously produce H_(2) and N-benzylidenebenzylamine without using any other sacrificial reagent.In situ characterizations and DFT calculations reveal that the alkali ions notably promote charge transport,while the nitrogen defects generate abundant edge active sites,which further contribute to efficient electron excitation to trigger photoredox reactions.展开更多
Fluorescence imaging techniques represent essential tools in in vitro,preclinical,and clinical studies.In this study,an improved one-step hydrothermal method to synthesize citric acid(CA)modifiedα-NaYbF_(4):2%Er^(3+)...Fluorescence imaging techniques represent essential tools in in vitro,preclinical,and clinical studies.In this study,an improved one-step hydrothermal method to synthesize citric acid(CA)modifiedα-NaYbF_(4):2%Er^(3+)nanocrystals was proposed.The introduction of various doping ions into NaYbF_(4):2%Er^(3+)and the different valence states of the same ions affect both the crystal size and upconversion luminesce nce.There fore,we investigated the upconversion luminesce nce enha ncement of NaYbF_(4):2%Er^(3+)by ion doping and find that the upconversion luminescence intensity of the upconversion nanoparticles(UCNPs)co-doped with 5 mol%Fe^(2+)ions shows the greatest enhancement,especially for red emission at654 nm.Furthermore,HeLa cells incubated with UCNPs allow for imaging with strong red upconversion emission detectio n.Confocal laser scanning microscope(CLSM)fluorescent images of HeLa cells indicate that NaYbF_(4):2%Er/5%Fe^(2+)leads to a clear outline and improves visualization of the cell morphology.In addition,the CA coated NaYbF_(4):2%Er^(3+)/5%Fe^(2+)nanoparticles and NaYbF_(4):2%Er^(3+)/5%Fe^(2+)show low cytotoxicity in HeLa cells.Organ imaging reveals the efficiency of these UCNPs to analyze the lungs,liver,and spleen.Together,these results indicate that the Cit-NaYbF_(4):2%Er^(3+)/5%Fe^(2+)UCNPs are efficient nanoprobes for fluorescence molecular to mography.展开更多
In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was ev...In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.展开更多
The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra wer...The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra were used to characterize the Yb^3+ doped Bi2WO6 photocatalysts.The morphology,specific surface area,and pore volume distribution were greatly affected after Yb3+ ions doping.Photocatalytic performance of Bi2WO6 was effectively enhanced after Yb3+ ions doping,6% Yb^3+ doped Bi2WO6 had the best photocatalytic performance,and 96.2% Rhodamine B was degradated after irradiated 30 min,which was 1.29 times that of the pristine one.The enhanced photocatalytic performance was due to the increased specific surface area,decreased energy band gap and inhibition of photoelectron-hole recombination after Yb3+ ions doping.展开更多
Antimony selenide(Sb_(2)Se_(3))has drawn tremendous research attentions in recent years as an environment-friendly and cost-efficient photovoltaic material.However,the intrinsic low carrier density and electrical cond...Antimony selenide(Sb_(2)Se_(3))has drawn tremendous research attentions in recent years as an environment-friendly and cost-efficient photovoltaic material.However,the intrinsic low carrier density and electrical conductivity limited its scope of applications.In this work,an effective ion doping strategy was implemented to improve the electrical and photoelectrical performances of Sb_(2)Se_(3) thin films.The Sn-doped and I-doped Sb_(2)Se_(3) thin films with controllable chemical composition can be prepared by magnetron sputtering combined with post-selenization treatment based on homemade plasma sintered targets.As a result,the Sn-doped Sb_(2)Se_(3) thin film exhibited a great increase in carrier density by several orders of magnitude,by contrast,a less increase with one order of magnitude was achieved for the Idoped Sb_(2)Se_(3) thin film.Additionally,such cation or anion doping could simultaneously modify the conduction type of Sb_(2)Se_(3),enabling the first fabrication of a substrate structured Sb_(2)Se_(3)-based quasihomojunction thin film solar cell with configuration of Mo/Sb_(2)Se_(3)-Sn/Sb_(2)Se_(3)-I/ITO/Ag.The obtained power conversion efficiency exceeding 2%undoubtedly demonstrated its attractive photovoltaic application potential and further investigation necessity.展开更多
The polymer-based solid-state electrolytes (PSEs) are promising for solid-state batteries but they have deficiencies such as low ionic conductivity, low lithium-ion transference number, and unstable electrode/electrol...The polymer-based solid-state electrolytes (PSEs) are promising for solid-state batteries but they have deficiencies such as low ionic conductivity, low lithium-ion transference number, and unstable electrode/electrolyte interface. Herein, we designed a hydroxyapatite nanowire doped with high-valence cations in anticipation of the formation of positively charged active sites on the nanowire surface. The higher surface activity can reduce the reaction activation energy on the nanowire surface and adsorb the anions in the PSEs as a way to improve the ionic conductivity and Li+ transference number of the PSEs. The active sites on the surface of the nanowires anchor the anions, thus increasing the Li+ transference number to 0.38, which effectively improves the ionic conductivity of the PSE to 1.58 × 10-4 S cm-1 at room temperature. At the same time, the composite polymer electrolyte has a wide electrochemical window. The lithium symmetric cell stably cycles for 800 h at a current density of 0.1 mA cm-2, and the LiFePO4||Li full cell steadily cycles for 180 cycles at a rate of 0.5 C with a capacity retention of 94.2 %. The ion doping strategy to change the surface electrical behavior of nanowires provides an idea to improve the ionic conductivity of solid-state electrolytes.展开更多
LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare...LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3＋, Ce3＋, Nd3＋, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM） and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests. The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3＋, Ce3＋ and Nds＋ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3＋ and Ce3＋ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3＋ exhibited the optimal electrochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, respectively.展开更多
In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as...In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.展开更多
A series of nanosized ion-doped TiO2 catalysts with different ion content （between 0.1 at.% and 1.0 at.%） have been prepared by wet impregnation method and investigated with respect to their behavior for UV photocat...A series of nanosized ion-doped TiO2 catalysts with different ion content （between 0.1 at.% and 1.0 at.%） have been prepared by wet impregnation method and investigated with respect to their behavior for UV photocatalytic oxidation of nitric oxide. The catalytic activity was correlated with structural, electronic and surface examinations of the catalysts using X-ray diffraction analysis （XRD）, ultraviolet-visible （UV-Vis） absorption spectroscopy, transmission electron microscopy （TEM）, energy disperse spectrometer （EDS） and high resolution-transmission electron microscopy （HR-TEM） techniques. An enhancement of the photocatalytic activity was observed for Zn2＋ doping catalyst ranged from 0.1 at.% to 1.0 at.% which was attributed to the lengthened lifetime of electrons and holes. The improvement in photocatalytic activity could be also observed with the low doping concentration of Cr^3＋ （0.1 at.%）. However, the doping of Fe^3＋, Mo^6＋, Mn^2＋ and the high doping concentration of Cr^3＋ had no contribution to photocatalytic activity of nitric oxide.展开更多
Ribbon-like Cu doped V6O（13） was synthesized via a simple solvothermal approach followed by heat treatment in air.As an cathode material for lithium ion battery,the ribbon-like Cu doped V6O（13 ）electrode exhibited...Ribbon-like Cu doped V6O（13） was synthesized via a simple solvothermal approach followed by heat treatment in air.As an cathode material for lithium ion battery,the ribbon-like Cu doped V6O（13 ）electrode exhibited good capacity retention with a reversible capacity of over 313 m Ah·g^-1 for up to 50 cycles at 0.1C,as well as a high charge capacity of 306 m Ah·g^-1 at a high current rate of 1 C,in comparison to undoped V6O（13 ）electrode（267 m Ah·g^-1 at 0.1C and 273 m Ah·g^-1 at 1 C）.The high rate capability and better cycleability of the doped electrode can be attributed to the influence of the Cu ions on the mophology and the electronic conductivity of V6O（13） during the lithiation and delithiation process.展开更多
In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK...In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK/Ce=0-0.30) on the phase composition,crystal structure,chromaticity and thermal stability ofγ-Ce2 S3 were systematically investigated.Pure γ-Ce2 S3 was obtained by calcining the doped samples at840℃ for 150 min.After calcination at the same temperature the undoped K+samples exhibit a pure α-phase.Samples with a K/Ce molar ratio(nK/Ce) of 0.10-0.25 comprise only the γ-phase;and when nK/Ce exceeds 0.25,a new heterogeneous phase,KCeS2,emerges.For values of nK/Ce in the range of0-0.25,the γ-Ce2 S3 lattice parameters gradually increases with increasing K+ content.When nK/Ceexceedes 0.25,the lattice parameters remains unchanged.As nK/Ce increased,the synthesized color gradually changes from red to orange—red and finally,to yellow.The redness value a* reaches the maximum(L*=33.86,a*=36.68,b*=38.15) when nK/Ce=0.10,The nK/Ce=0.10 composition continues to exhibit the y-phase after heat treatment at 420℃ for 10 min in air.The K+doping fills the internal vacancies of γ-Ce2 S3 and formed a solid solution,which is beneficial for the stability of its lattice,thus improving the thermal stability of γ-Ce2 S3(from 350 to 420℃).展开更多
Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and ...Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and charge-discharge test in this paper. The results show that a good clad coated on parent material can be synthesized by the sol-gel method, and the materials with modification have perfect spinel structure. LiCo0.09Mn1.91O3.92F0.08 materials coated by LiCoO2 improve the stability of crystal structure and decrease the dissolution of Mn into electrolyte. With the LiCoO2 content increasing, the specific capacity and cycle performance of samples are improved. The capacity loss is also suppressed distinctly even at 55 ℃.展开更多
The lanthanum trivalent ion doped TiO2 nanopowders were prepared by liquid plasma spray with solution of titanium tetra-tert-butoxide and alcohol as feedstock and La(NO3)3·6H2O as doping component. The photocatal...The lanthanum trivalent ion doped TiO2 nanopowders were prepared by liquid plasma spray with solution of titanium tetra-tert-butoxide and alcohol as feedstock and La(NO3)3·6H2O as doping component. The photocatalytic activity of samples at different doping concentrations in photocatalytic degradation of methyl orange was discussed. The powders were characterized by Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD), and the effect of doped ion on the pattern, phase composition and crystallite sizes were analyzed. The results indicated that lanthanum trivalent ion doped TiO2 nanopowders could be prepared by liquid plasma spray. Lanthanum trivalent ion doping increased the photocatalytic activity of TiO2 greatly, the optimal doping concentration was 0.5%. The doped powders were the mixture of anatase phase and rutile phase. The contents of anatase phase decreased firstly and then increased with an increase in the contents of lanthanum trivalent ion. Doping lanthanum trivalent ion could make the TiO2 nanopowders uniform and reduced its particle size.展开更多
基金financially supported by the Scientific Research Startup Fund for Shenzhen High-Caliber Personnel of SZPT(No.6021310029K)Research Projects of Department of Education of Guangdong Province(No.2023KTSCX319)。
文摘It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.
基金supported by the National Natural Science Foundation of China(No.52062019)the Natural Science Research Project of Higher Education Institutions in Jiangsu Province,China(No.24KJA430013)the Natural Science Foundation of Jiangsu Province for Youths,China(No.BK20230662)。
文摘All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.
基金supported by the Guangxi Natural Science Foundation(Grant No.2025GXNSFDA069038)The Guangxi Science and Technology Plan Project(Grant No.AA23073018)+1 种基金the National Natural Science Foundation of China(Grant Nos.22175043 and 52162021)the Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures(Grant No.MMCS2023OF05).
文摘Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence quantum yields(PLQY)restrict further applications.In this study,we synthesized Al^(3+),Er^(3+)-co-doped Gd_(3)Ga_(5)O_(12) garnets with multimode luminescence via a high-temperature solid-state method.Notably,the preferential substitution of Al^(3+)ion at octahedral-coordinated GaI sites significantly enhanced the charge density and electron transition probability,achieving a PLQY enhancement of the downshifting luminescence from 35.1%to 68.5%.Al^(3+)ion also influences electron relaxation during up-conversion luminescence,resulting in a color shift from red to yellow to green.Additionally,Al^(3+)incorporation increased the photoelectric conversion efficiency of light-emitting diodes from 2.9%to 6.3%and improved temperature sensing sensitivity from 2.7%to 5.1%K⁻1.This work provides new insights into the photophysical mechanisms and underscores the key role of Al^(3+)ion in optimizing the optical properties of garnet-based materials.
基金financially supported by the National Natural Science Foundation of China(No.51972095).
文摘The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrogen production from water splitting.In this work,M-MnO_(2)@TNTA composite electrodes were prepared by depositing various metal ion-doped manganese oxide nanoparticles on the titania nanotube array(TNTA)by successive ionic layer adsorption reaction(SILAR)method,and their HER and OER electrocatalytic performances were investigated in 1 M KOH.Results show that the CoFe-MnO_(2)@TNTA composite electrode prepared by simultaneous doping of Co^(3+)and Fe^(3+)in MnO_(2) exhibits optimal catalytic performance.Compared with MnO_(2)@TNTA without ion doping,the overpotentials of CoFe-MnO_(2)@TNTA at 10 mA cm^(-2)(η_(10))for HER and OER are reduced by 571 and 665 mV.In addition,the electrode perfor-mance can be significantly enhanced by increasing the test temperature,and the porous array structure enables CoFe-MnO_(2)@TNTA to exhibit better performance at high current densities.At 50℃,which is the common industrial electrolytic water temperature,the η_(10) of CoFe-MnO_(2)@TNTA for HER is almost equal to that of the Pt/C electrode.The η_(100) of CoFe-MnO_(2)@TNTA for HER is reduced by 35 mV compared with the Pt/C electrode.Moreover,η_(200) of CoFe-MnO_(2)@TNTA for OER is significantly lowered by 111 and 184 mV compared with IrO_(2) and RuO_(2) electrodes.Utilizing CoFe-MnO_(2)@TNTA as both the cathode and anode for overall water splitting,the electrolysis voltage is merely 2.33 V under the current density of 200 mA cm^(-2),much lower than that of IrO_(2)(+)||Pt/C(-)(2.68 V).The present work may provide a valuable reference for the development of self-supporting bifunctional electrodes suitable for high-current-density water splitting at industrial temperatures.
文摘Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal environmental impact.However,these materials suffer from poor rate capability and low-temperature performance owing to limited electronic and ionic conductivity,which restricts their practical applicability.Recent developments,such as coating material particles with carbon or a conductive polymer,crystal deformation through the doping of foreign metal ions,and the production of nanostructured materials,have significantly enhanced the electrochemical performances of these materials.The successful applications of polyanion-based materials,especially in lithium-ion batteries,have been extensively reported.This comprehensive review discusses the current progress in crystal deformation in polyanion-based cathode materials,including phosphates,fluorophosphates,pyrophosphates,borates,silicates,sulfates,fluorosilicates,and oxalates.Therefore,this review provides detailed discussions on their synthesis strategies,electrochemical performance,and the doping of various ions.
文摘Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.
基金supported by the National Key Research and Development Program of the MOST(Nos.2021YFA1500400 and 2018YFA0208603)the National Natural Science Foundation of China(NSFC,Nos.21571167,51502282,22075266,and 21890751)the Fundamental Research Funds for the Central Universities(Nos.WK2060190053 and WK2060190100).
文摘Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampered by the poor charge carrier transport and high recombination.Herein,we develop a facile salt template-assisted interfacial polymerization strategy that insitu introduces alkali ions(Na+,K+)and nitrogen defects in CN(denoted as v-CN-KNa)to simultaneously promote charge separation and transportation and steer photoexcited holes and electrons to their oxidation and reduction sites.The photocatalyst exhibits an impressive photocatalytic H_(2) evolution rate of 8641.5μmol·g^(−1)·h^(−1)(33-fold higher than pristine CN)and also works readily in real seawater(10752.0μmol·g^(−1)·h^(−1))with a high apparent quantum efficiency up to 18.5%at 420 nm.In addition,we further demonstrate that the v-CN-KNa can simultaneously produce H_(2) and N-benzylidenebenzylamine without using any other sacrificial reagent.In situ characterizations and DFT calculations reveal that the alkali ions notably promote charge transport,while the nitrogen defects generate abundant edge active sites,which further contribute to efficient electron excitation to trigger photoredox reactions.
基金Project supported by the Natural Science Basic Research Program of Shaanxi Province(2021JZ-43)the Key Program for International Science and Technology Cooperation Projects of Shaanxi Province(2018KWZ-08)+2 种基金the National Key Research and Development Program of China(2019YFC1520904)the Scientific Research Plan of Shannxi Provincial Education Department,China(18JK0780)Ningxia Natural Fund(2023AAC03338)。
文摘Fluorescence imaging techniques represent essential tools in in vitro,preclinical,and clinical studies.In this study,an improved one-step hydrothermal method to synthesize citric acid(CA)modifiedα-NaYbF_(4):2%Er^(3+)nanocrystals was proposed.The introduction of various doping ions into NaYbF_(4):2%Er^(3+)and the different valence states of the same ions affect both the crystal size and upconversion luminesce nce.There fore,we investigated the upconversion luminesce nce enha ncement of NaYbF_(4):2%Er^(3+)by ion doping and find that the upconversion luminescence intensity of the upconversion nanoparticles(UCNPs)co-doped with 5 mol%Fe^(2+)ions shows the greatest enhancement,especially for red emission at654 nm.Furthermore,HeLa cells incubated with UCNPs allow for imaging with strong red upconversion emission detectio n.Confocal laser scanning microscope(CLSM)fluorescent images of HeLa cells indicate that NaYbF_(4):2%Er/5%Fe^(2+)leads to a clear outline and improves visualization of the cell morphology.In addition,the CA coated NaYbF_(4):2%Er^(3+)/5%Fe^(2+)nanoparticles and NaYbF_(4):2%Er^(3+)/5%Fe^(2+)show low cytotoxicity in HeLa cells.Organ imaging reveals the efficiency of these UCNPs to analyze the lungs,liver,and spleen.Together,these results indicate that the Cit-NaYbF_(4):2%Er^(3+)/5%Fe^(2+)UCNPs are efficient nanoprobes for fluorescence molecular to mography.
基金Project supported by Beijing Excellent Talents Training Fund (20061D0502200299)
文摘In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.
基金the National Natural Science Foundation of China(No.51662005)。
文摘The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra were used to characterize the Yb^3+ doped Bi2WO6 photocatalysts.The morphology,specific surface area,and pore volume distribution were greatly affected after Yb3+ ions doping.Photocatalytic performance of Bi2WO6 was effectively enhanced after Yb3+ ions doping,6% Yb^3+ doped Bi2WO6 had the best photocatalytic performance,and 96.2% Rhodamine B was degradated after irradiated 30 min,which was 1.29 times that of the pristine one.The enhanced photocatalytic performance was due to the increased specific surface area,decreased energy band gap and inhibition of photoelectron-hole recombination after Yb3+ ions doping.
基金supported by Natural Science Foundation of Guangdong Province(2020A1515010805)ChinaNational Natural Science Foundation of China(No.62074102)+1 种基金Key Project of Department of Education of Guangdong Province(No.2018KZDXM059)ChinaScience and Technology plan project of Shenzhen(JCYJ20190808153409238)China.
文摘Antimony selenide(Sb_(2)Se_(3))has drawn tremendous research attentions in recent years as an environment-friendly and cost-efficient photovoltaic material.However,the intrinsic low carrier density and electrical conductivity limited its scope of applications.In this work,an effective ion doping strategy was implemented to improve the electrical and photoelectrical performances of Sb_(2)Se_(3) thin films.The Sn-doped and I-doped Sb_(2)Se_(3) thin films with controllable chemical composition can be prepared by magnetron sputtering combined with post-selenization treatment based on homemade plasma sintered targets.As a result,the Sn-doped Sb_(2)Se_(3) thin film exhibited a great increase in carrier density by several orders of magnitude,by contrast,a less increase with one order of magnitude was achieved for the Idoped Sb_(2)Se_(3) thin film.Additionally,such cation or anion doping could simultaneously modify the conduction type of Sb_(2)Se_(3),enabling the first fabrication of a substrate structured Sb_(2)Se_(3)-based quasihomojunction thin film solar cell with configuration of Mo/Sb_(2)Se_(3)-Sn/Sb_(2)Se_(3)-I/ITO/Ag.The obtained power conversion efficiency exceeding 2%undoubtedly demonstrated its attractive photovoltaic application potential and further investigation necessity.
基金financially supported by the National Natural Science Foundation of China(Nos.52272234 and 51832004)the Key Research and Development Program of Hubei Province(No.2021BAA070)+1 种基金the Independent Innovation Projects of the Hubei Longzhong Laboratory(No.2022ZZ-20)the Sanya Science and Education Innovation Park of Wuhan University of Technology(No.2021KF0011).
文摘The polymer-based solid-state electrolytes (PSEs) are promising for solid-state batteries but they have deficiencies such as low ionic conductivity, low lithium-ion transference number, and unstable electrode/electrolyte interface. Herein, we designed a hydroxyapatite nanowire doped with high-valence cations in anticipation of the formation of positively charged active sites on the nanowire surface. The higher surface activity can reduce the reaction activation energy on the nanowire surface and adsorb the anions in the PSEs as a way to improve the ionic conductivity and Li+ transference number of the PSEs. The active sites on the surface of the nanowires anchor the anions, thus increasing the Li+ transference number to 0.38, which effectively improves the ionic conductivity of the PSE to 1.58 × 10-4 S cm-1 at room temperature. At the same time, the composite polymer electrolyte has a wide electrochemical window. The lithium symmetric cell stably cycles for 800 h at a current density of 0.1 mA cm-2, and the LiFePO4||Li full cell steadily cycles for 180 cycles at a rate of 0.5 C with a capacity retention of 94.2 %. The ion doping strategy to change the surface electrical behavior of nanowires provides an idea to improve the ionic conductivity of solid-state electrolytes.
基金Technology Innovation Foundation Project for Outstanding Youth of Hebei Uninversity of Technology for financial support
文摘LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3＋, Ce3＋, Nd3＋, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM） and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests. The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3＋, Ce3＋ and Nds＋ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3＋ and Ce3＋ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3＋ exhibited the optimal electrochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, respectively.
基金supported by the National Natural Science Foundation of China (52202001)Open Project of Advanced Laser Technology Laboratory of Anhui Province (AHL2021KF07)+1 种基金Major Science and Technology of Anhui Province(202203a05020002)University Natural Science Research Project of Anhui Province (KJ2021A0388)。
文摘In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.
基金Porject supported by the New Century Excellent Scholar Program of Ministry of Education of China(No.NCET-04-0549)the China Postdoctoral Science Foundation(No.20060401047).
文摘A series of nanosized ion-doped TiO2 catalysts with different ion content （between 0.1 at.% and 1.0 at.%） have been prepared by wet impregnation method and investigated with respect to their behavior for UV photocatalytic oxidation of nitric oxide. The catalytic activity was correlated with structural, electronic and surface examinations of the catalysts using X-ray diffraction analysis （XRD）, ultraviolet-visible （UV-Vis） absorption spectroscopy, transmission electron microscopy （TEM）, energy disperse spectrometer （EDS） and high resolution-transmission electron microscopy （HR-TEM） techniques. An enhancement of the photocatalytic activity was observed for Zn2＋ doping catalyst ranged from 0.1 at.% to 1.0 at.% which was attributed to the lengthened lifetime of electrons and holes. The improvement in photocatalytic activity could be also observed with the low doping concentration of Cr^3＋ （0.1 at.%）. However, the doping of Fe^3＋, Mo^6＋, Mn^2＋ and the high doping concentration of Cr^3＋ had no contribution to photocatalytic activity of nitric oxide.
基金Funded by the Program for New Century Excellent Talents in University of Ministry of Education,(No.NCET-12-0655)the Guangxi Natural Science Foundation(No.2014GXNSFFA118004)
文摘Ribbon-like Cu doped V6O（13） was synthesized via a simple solvothermal approach followed by heat treatment in air.As an cathode material for lithium ion battery,the ribbon-like Cu doped V6O（13 ）electrode exhibited good capacity retention with a reversible capacity of over 313 m Ah·g^-1 for up to 50 cycles at 0.1C,as well as a high charge capacity of 306 m Ah·g^-1 at a high current rate of 1 C,in comparison to undoped V6O（13 ）electrode（267 m Ah·g^-1 at 0.1C and 273 m Ah·g^-1 at 1 C）.The high rate capability and better cycleability of the doped electrode can be attributed to the influence of the Cu ions on the mophology and the electronic conductivity of V6O（13） during the lithiation and delithiation process.
基金Project supported by National Natural Science Foundation of China (51462010)Natural Science Foundation of Jiangxi Province(20161BAB206132,20171ACB20022)The Innovation fund of Jingdezhen Ceramic Institute (JYC-201803)。
文摘In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK/Ce=0-0.30) on the phase composition,crystal structure,chromaticity and thermal stability ofγ-Ce2 S3 were systematically investigated.Pure γ-Ce2 S3 was obtained by calcining the doped samples at840℃ for 150 min.After calcination at the same temperature the undoped K+samples exhibit a pure α-phase.Samples with a K/Ce molar ratio(nK/Ce) of 0.10-0.25 comprise only the γ-phase;and when nK/Ce exceeds 0.25,a new heterogeneous phase,KCeS2,emerges.For values of nK/Ce in the range of0-0.25,the γ-Ce2 S3 lattice parameters gradually increases with increasing K+ content.When nK/Ceexceedes 0.25,the lattice parameters remains unchanged.As nK/Ce increased,the synthesized color gradually changes from red to orange—red and finally,to yellow.The redness value a* reaches the maximum(L*=33.86,a*=36.68,b*=38.15) when nK/Ce=0.10,The nK/Ce=0.10 composition continues to exhibit the y-phase after heat treatment at 420℃ for 10 min in air.The K+doping fills the internal vacancies of γ-Ce2 S3 and formed a solid solution,which is beneficial for the stability of its lattice,thus improving the thermal stability of γ-Ce2 S3(from 350 to 420℃).
文摘Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and charge-discharge test in this paper. The results show that a good clad coated on parent material can be synthesized by the sol-gel method, and the materials with modification have perfect spinel structure. LiCo0.09Mn1.91O3.92F0.08 materials coated by LiCoO2 improve the stability of crystal structure and decrease the dissolution of Mn into electrolyte. With the LiCoO2 content increasing, the specific capacity and cycle performance of samples are improved. The capacity loss is also suppressed distinctly even at 55 ℃.
基金the Natural Science Foundation of Shannxi ,China (2005E103)
文摘The lanthanum trivalent ion doped TiO2 nanopowders were prepared by liquid plasma spray with solution of titanium tetra-tert-butoxide and alcohol as feedstock and La(NO3)3·6H2O as doping component. The photocatalytic activity of samples at different doping concentrations in photocatalytic degradation of methyl orange was discussed. The powders were characterized by Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD), and the effect of doped ion on the pattern, phase composition and crystallite sizes were analyzed. The results indicated that lanthanum trivalent ion doped TiO2 nanopowders could be prepared by liquid plasma spray. Lanthanum trivalent ion doping increased the photocatalytic activity of TiO2 greatly, the optimal doping concentration was 0.5%. The doped powders were the mixture of anatase phase and rutile phase. The contents of anatase phase decreased firstly and then increased with an increase in the contents of lanthanum trivalent ion. Doping lanthanum trivalent ion could make the TiO2 nanopowders uniform and reduced its particle size.
