NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.A...NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.展开更多
In this study,we aim to clarify the luminescence and scintillation performance of 0.2 at%Pr^(3+)-doped LuYAG scintillators with either zirconium or hafnium co-doping obtained using the micro-pulling-down(μ-PD)method....In this study,we aim to clarify the luminescence and scintillation performance of 0.2 at%Pr^(3+)-doped LuYAG scintillators with either zirconium or hafnium co-doping obtained using the micro-pulling-down(μ-PD)method.Under radiation excitation,scintillation properties such as light yield,decay time,and afterglow level were measured and compared to non-co-doped LuYAG:Pr^(3+).The positive effect of Zr and Hf co-doping is to significantly shorten the scintillation time response.The negative effect is the decrease of scintillation yield and increase of afterglow.We propose that the positively charged defects induced by Zr/Hf co-doping are responsible for the spatial correlated traps around Pr centers causing the shortened scintillation decay via non-radiative recombination processes,and the deep traps as well for the prolonged afterglow.展开更多
The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capac...The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.展开更多
Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature condit...Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.展开更多
Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hi...Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.展开更多
Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical ...Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical conductivity,poor structural stability and inefficient nanostructure.Herein,we report a novel Cu0/Cu+co-doped CoO composite with adjustable metallic Cu0 and ion Cu+via a facile strategy.Through interior(Cu+)and exterior(Cu0)decoration of CoO,the electrochemical performance of CoO electrode has been significantly improved due to both the beneficial flower-like nanostructure and the synergetic effect of Cu0/Cu+co-doping,which results in a significantly enhanced specific capacitance(695 F g^(-1) at 1 A g^(-1))and high cyclic stability(93.4%retention over 10,000 cycles)than pristine CoO.Furthermore,this co-doping strategy is also applicable to other transition metal oxide(NiO)with enhanced electrochemical performance.In addition,an asymmetric hybrid supercapacitor was assembled using the Cu0/Cu+co-doped CoO electrode and active carbon,which delivers a remarkable maximal energy density(35 Wh kg^(-1)),exceptional power density(16 kW kg^(-1))and ultralong cycle life(91.5%retention over 10,000 cycles).Theoretical calculations further verify that the co-doping of Cu^(0)/Cu^(+)can tune the electronic structure of CoO and improve the conductivity and electron transport.This study demonstrates a facile and favorable strategy to enhance the electrochemical performance of transition metal oxide electrode materials.展开更多
Green light-emitting Ba2SiO4：Eu^2＋ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere（a mixture of 5% H2 and 95% N2）.The results showed that the...Green light-emitting Ba2SiO4：Eu^2＋ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere（a mixture of 5% H2 and 95% N2）.The results showed that the co-doping of La and Y could greatly enhance the fluorescence intensity of Ba2SiO4：Eu2＋ phosphors.The optimum doping concentration expressed by the x value in（Ba0.985-1.5xREx）2SiO4：0.03Eu^2＋（RE=La or Y） was determined to be of 0.05.The excitation and emission peaks of all as-synthesized phosphors were wide bands.The excitation bands ranged from 250 to 400 nm, which matched well with the wavelength of near ultraviolet white light-emitting diodes（LED） chip and could be used as a potential candidate for the fabrication of white LED.The emission bands from 450 to 550 nm were typical 5d-4f transition emission of Eu^2＋ and displayed un-symmetry profiles because of the two substitution sites of Ba^2＋ with Eu^2＋.展开更多
It is well known that Tb substitution for(Pr,Nd)in(Pr,Nd)-Fe-B based sintered magnetic materials is an effective way to increase intrinsic coercivity,but it is not quite clear whether the increment depends on the diff...It is well known that Tb substitution for(Pr,Nd)in(Pr,Nd)-Fe-B based sintered magnetic materials is an effective way to increase intrinsic coercivity,but it is not quite clear whether the increment depends on the different matrix phases with various doping ingredient or not,which is essential to develop high quality magnets with high coercivity more efficiently and effectively with economic consumption of expensive Tb and other costly heavy rare earths.In this paper,we investigated the efficiency of Tb substitution for magnetic property in(Pr,Nd)-Fe-B sintered permanent magnets by co-doping Ga and Cu elements.It is shown that Ga and Cu co-doping can effectively improve the efficiency of Tb substitution to increase the thermal stability and the coercivity.The intrinsic coercivity increases up to 549 and 987 kA/m respectively by 1.5 wt%and 3.0 wt%Tb substitution in Ga and Cu co-doped magnets while the intrinsic coercivity increases up to only 334 and 613 kA/m respectively by the same amounts of Tb substitution in non-Ga and low-Cu magnets.In other words,it demonstrates that there is about 329-366 kA/m linear equivalent enhancement of intrinsic coercivity by 1.0 wt%Tb substitution for(Pr,Nd)in Ga and Cu co-doped magnets.The temperature coefficients of both intrinsic coercivityβand remanenceαat 20-150℃by 3.0 wt%Tb substitution for the magnets with Ga and Cu co-doping are-0.47%/K and-0.109%/K respectively,and in contrast those values are-0.52%/K and 0.116%/K respectively for the non-Ga and low-Cu magnets.It is the principal reason for more efficient enhancement of magnetic property by Tb substitution in the Ga and Cu co-doped magnets in which Tb atoms are expelled from triple junction phases(TJPs)to penetrate into the grain boundary phases(GB phases)and thus modify the grain boundary.It is prospected that the efficiency of Tb substitution would rely on different matrix phases with various doping constituents.展开更多
The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, w...The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, were studied within the temperature interval of 6–300 K. At the 6 K temperature in the visible spectral range 2 bands were observed： a band in the excitonic spectral region and a band of self-activated luminescence. It was shown that co-doping of zinc selenide crystals with the chromium and ytterbium led to the combination of the impurities influence on the photoluminescent properties. At the liquid helium temperature in the middle infrared range of the spectra of the ytterbium and chromium co-doped crystal a band with the maximum localized at 1.7μm was observed, which was overlapped with a complex band in the middle-IR spectral range, characteristic for the chromium doped ZnSe crystals. On the basis of obtained data an interaction mechanism of the chromium and ytterbium co-doping impurities was proposed. Guided by the existent model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made. It was assumed that the resonant energy transfer from one chromium ion to another,which led to the concentration quenching of the IR emission in the ZnSe：Cr PL spectra, would lead to the broadening of the IR emission in the spectra of ytterbium and chromium co-doped zinc selenide crystals.g展开更多
The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the den...The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the density functional theory. The calculated results show that the carrier concentration is increased in the ZnO crystal codoped by N and Ag, and the codoped structure is stable and is more in favour of the formation of p-type ZnO.展开更多
Layered LiCoO_(2)(LCO)acts as a dominant cathode material for lithium-ion batteries(LIBs)in 3C products because of its high compacted density and volumetric energy density.Although improving the high cutoff voltage is...Layered LiCoO_(2)(LCO)acts as a dominant cathode material for lithium-ion batteries(LIBs)in 3C products because of its high compacted density and volumetric energy density.Although improving the high cutoff voltage is an effective strategy to increase its capacity,such behavior would trigger rapid capacity decay due to the surface or/and structure degradation.Herein,we propose a bi-functional surface strategy involving constructing a robust spinel-like phase coating layer with great integrity and compatibility to LiCoO_(2) and modulating crystal lattice by anion and cation gradient co-doping at the subsurface.As a result,the modified LiCoO_(2)(AFM-LCO)shows a capacity retention of 80.9%after 500 cycles between 3.0and 4.6 V.The Al,F,Mg enriched spinel-like phase coating layer serves as a robust physical barrier to effectively inhibit the undesired side reactions between the electrolyte and the cathode.Meanwhile,the Al,F,Mg gradient co-doping significantly enhances the surficial structure stability,suppresses Co dissolution and oxygen release,providing a stable path for Li-ions mobility all through the long-term cycles.Thus,the surface bi-functional strategy is an effective method to synergistically improve the electrochemical performances of LCO at a high cut-off voltage of 4.6 V.展开更多
Mn-Zn ferrites doped with different contents of Sm^（3＋） and Gd^（3＋） ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy（FTIR）, thermogravimetric an...Mn-Zn ferrites doped with different contents of Sm^（3＋） and Gd^（3＋） ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy（FTIR）, thermogravimetric analysis（TG）, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and vibrating sample magnetometer（VSM）. When samples were calcined in a relatively low temperature below 1100 °C, secondary phases（α-Fe_2O_3） could be identified. Therefore, in order to acquire pure and better crystallinity, the suitable calcining temperature of powders was selected at 1200 °C. It was also found that all the samples consisting of ferrite phases of typical spinel cubic structure and average crystallite sizes between 31.5 and 38.2 nm were obtained after calcining at 1200 oC for 4 h. The lattice parameters increased almost linearly with increasing Sm content. A dense microstructure was obtained after sintering at 1250 °C for 4 h. Through the analysis of magnetic properties, hysteresis loops for all the samples were narrow with low values of coercivity and retentivity, indicating the paramagnetic nature of these samples. And saturation magnetization Ms strongly depended on the type of additive to reach a maximum of 47.99 emu/g for x=0.015, which showed a great promise for hyperthermia applications.展开更多
Electrochemical reduction of CO_(2)(CERR)to value-added chemicals is an attractive strategy for greenhouse gas mitigation,and carbon recycles utilization.Conventional metal catalysts suffered from low durability and s...Electrochemical reduction of CO_(2)(CERR)to value-added chemicals is an attractive strategy for greenhouse gas mitigation,and carbon recycles utilization.Conventional metal catalysts suffered from low durability and sluggish kinetics impede the practical application.On the other hand,doped carbon materials recently demonstrate superior catalytic performance in CERR,which shows the potential to diminish the problems of metal catalysts to some extent.Herein,we present the design and fabrication of nitrogen(N),phosphorus(P)co-doped metal-free carbon materials as an efficient and stable electrocatalyst for reduction of CO_(2) to CO,which exhibits an excellent performance with a high faradaic efficiency of 92%(-0.55 V vs.RHE)and up to 24 h stability.A series of characterizations including TEM and XPS verified that nitrogen and phosphorous are successfully incorporated into the carbon matrix.Moreover,the comparisons between co-doping and single doping catalysts reveal that co-doping can significantly increase CERR performance.The improved catalytic activity is attributed to the synergetic effects between nitrogen and phosphorous dopants,which effectively modulate properties of the active site.The density functional theory(DFT)calculations were also performed to understand the synergy effects of dopants.It is revealed that the phosphorous doping can significantly lower the Gibbs free energy of COOH^(*)formation.Moreover,the introduction of the second dopants phosphorous can reduce the reaction barrier along the reaction path and cause polarization of density of states at the Fermi level.These changes can greatly enhance the activity of the catalysts.From a combined experimental and computational exploration,current work provides valuable insights into the reaction mechanism of CERR on N,P co-doped carbon catalysts,and the influence from synergy effects between dopants,which paves the way for the rational design of novel metal-free catalysts for CO2 electro-reduction.展开更多
The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long ...The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.展开更多
Biomass-derived carbon has demonstrated great potentials as advanced electrode for capacitive deionization(CDI),owing to good electroconductivity,easy availability,intrinsic pores/channels.However,conventional simple ...Biomass-derived carbon has demonstrated great potentials as advanced electrode for capacitive deionization(CDI),owing to good electroconductivity,easy availability,intrinsic pores/channels.However,conventional simple pyrolysis of biomass always generates inadequate porosity with limited surface area.Moreover,biomass-derived carbon also suffers from poor wettability and single physical adsorption of ions,resulting in limited desalination performance.Herein,pore structure optimization and element co-doping are integrated on banana peels(BP)-derived carbon to construct hierarchically porous and B,N co-doped carbon with large ions-accessible surface area.A unique expansionactivation(EA)strategy is proposed to modulate the porosity and specific surface area of carbon.Furthermore,B,N co-doping could increase the ions-accessible sites with improved hydrophilicity,and promote ions adsorption.Benefitting from the synergistic effect of hierarchical porosity and B,N co-doping,the resultant electrode manifest enhanced CDI performance for NaCl with large desalination capacity(29.5 mg g^(-1)),high salt adsorption rate(6.2 mg g^(-1)min^(-1)),and versatile adsorption ability for other salts.Density functional theory reveals the enhanced deionization mechanism by pore and B,N co-doping.This work proposes a facile EA strategy for pore structure modulation of biomass-derived carbon,and demonstrates great potentials of integrating pore and heteroatoms-doping on constructing high-performance CDI electrode.展开更多
Using the first-principles calculations, we investigate the electronic band structure and the quantum transport properties of metallic carbon nanotubes （MCNTs） with B/N pair co-doping. The results about formation en...Using the first-principles calculations, we investigate the electronic band structure and the quantum transport properties of metallic carbon nanotubes （MCNTs） with B/N pair co-doping. The results about formation energy show that the B/N pair co-doping configuration is a most stable structure. We find that the electronic structure and the transport properties are very sensitive to the doping concentration of the B/N pairs in MCNTs, where the energy gaps increase with doping concentration increasing both along the tube axis and around the tube, because the mirror symmetry of MCNT is broken by doping B/N pairs. In addition, we discuss conductance dips of the transmission spectrum of doped MCNTs. These unconventional doping effects could be used to design novel nanoelectronic devices.展开更多
The Ni-ultrahigh cathode material is one of the best choices for further increasing energy-density of lithium-ion batteries(LIBs),but they generally suffer from the poor structure stability and rapid capacity fade.Her...The Ni-ultrahigh cathode material is one of the best choices for further increasing energy-density of lithium-ion batteries(LIBs),but they generally suffer from the poor structure stability and rapid capacity fade.Herein,the tungsten and phosphate polyanion co-doped LiNi_(0.9)Co_(0.1)O_(2)cathode materials are successfully fabricated in terms of Li(Ni_(0.9)Co_(0.7))_(1-x)W_(x)O_(2-4y)(PO_(4))_(y) by the precursor modification and subsequent annealing.The higher bonding energy of W—O(672 kJ·mol^(-1))can extremely stabilize the lattice oxygen of Ni-rich oxides compared with Ni—O(391.6 kJ·mol^(-1))and Co—O(368 kJ·mol^(-1)).Meanwhile,the stronger bonding of Ni—(PO_(4)^(3-))vs.Ni—O could fix Ni cations in the transition metal layer,and hence suppressing the Li/Ni disorder during the charge/discharge process.Therefore,the optimized Li(Ni_(0.9)Co_(0.1))_(0.99)W_(0.01)O_(1.96)(PO_4)_(0.01)delivers a remarkably extended cycling life with 95.1%retention of its initial capacity of 207.4 mA·h·g^(-1)at 0.2 C after 200 cycles.Meantime,the heteroatoms doping does not sacrifice the specific capacity even at different rates.展开更多
In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 a...In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 at%Eu,x at%Pr(x=0,0.2,0.5,1,2 and 5)and(Lu1-yScy)_(2)O_(3):5 at%Eu(y=0,20 at%,50 at%and 70 at%)single crystals were grown by floating zone(FZ)method in air atmosphere.The structures of as-grown crystals were determined by X-ray diffraction(XRD).The scintillation,photoluminescence properties and carrier trap states were investigated through afterglow,X-ray excitation luminescence(XEL),transmittance,photoluminescence excitation(PLE)and photoluminescence(PL),PL decay and thermal stimulated luminescence(TSL)curves.It is found that with the increase of Pr^(3+)concentration,the afterglow level of the system decreases at the expense of scintillation luminescence efficiency.Meanwhile,although Sc_(2)O_(3):Eu presents much lower afterglow intensity than Lu_(2)O_(3):Eu,the addition of Sc_(2)O_(3)will just increase the afterglow level of the(Lu1-yScy)_(2)O_(3):5 at%Eu single crystal system.Possible mechanisms for above phenomena are discussed based on experimental results.展开更多
High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrot...High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrothermal method for the first time.After doping,the tex ture of nanosphere becomes loose,the nanometer diameter is reduced,making the specific surface area of catalyst increased from 34.73 to 101.59 m^(2)/g.The characterization results show that more ZnS (111) crystal planes are exposed by N/Cu co-doping;the calculations of density functional theory show that N/Cu co-doping can increase the catalytic activity of the ZnS (111) crystal plane,enhance the adsorption capacity of (111) crystal plane to O_(2)and promote the generation of·O_(2)-.The energy levels of the introduced impurities can be hybridized with the energy levels of S and Zn at the top of valence band and the bottom o conduction band,which makes the band gap narrower,thus enhancing the absorption o visible light.Compared with pure ZnS,the degradation rates of 2,4-dichlorophenol (2,4-DCP and tetracycline (TC) by N/Cu-ZnS under visible light (>420 nm) are increased by 83.7 and51 times,respectively.In this research,a promising photocatalyst for photocatalytic degra dation of organic pollutants in wastewater is provided.展开更多
The p-type doping efficiency of 4 H silicon carbide(4 H-SiC)is rather low due to the large ionization energies of p-type dopants.Such an issue impedes the exploration of the full advantage of 4 H-SiC for semiconductor...The p-type doping efficiency of 4 H silicon carbide(4 H-SiC)is rather low due to the large ionization energies of p-type dopants.Such an issue impedes the exploration of the full advantage of 4 H-SiC for semiconductor devices.In this study,we show that co-doping group-IVB elements effectively decreases the ionization energy of the most widely used p-type dopant,i.e.,aluminum(Al),through the defect-level repulsion between the energy levels of group-IVB elements and that of Al in 4 H-SiC.Among group-IVB elements Ti has the most prominent effectiveness.Ti decreases the ionization energy of Al by nearly 50%,leading to a value as low as~0.13 eV.As a result,the ionization rate of Al with Ti co-doping is up to~5 times larger than that without co-doping at room temperature when the doping concentration is up to 10^(18)cm^(-3).This work may encourage the experimental co-doping of group-IVB elements such as Ti and Al to significantly improve the p-type doping efficiency of 4 H-SiC.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22276182 and 22188102)the Natural Science Foundation of Fujian Province,China(No.2023J06048)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021303).
文摘NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.
基金supported by the National Key R&D Program of China(2022YFB3503900)National Natural Science Foundation of China(11975303,12211530561,12305211)+2 种基金Shanghai Municipal Natural Science Foundation(20ZR1473900,21TS1400100)CAS Cooperative Research Project(121631KYSB20210017)CAS Project for Young Scientist in Basic Research(YSBR-024)。
文摘In this study,we aim to clarify the luminescence and scintillation performance of 0.2 at%Pr^(3+)-doped LuYAG scintillators with either zirconium or hafnium co-doping obtained using the micro-pulling-down(μ-PD)method.Under radiation excitation,scintillation properties such as light yield,decay time,and afterglow level were measured and compared to non-co-doped LuYAG:Pr^(3+).The positive effect of Zr and Hf co-doping is to significantly shorten the scintillation time response.The negative effect is the decrease of scintillation yield and increase of afterglow.We propose that the positively charged defects induced by Zr/Hf co-doping are responsible for the spatial correlated traps around Pr centers causing the shortened scintillation decay via non-radiative recombination processes,and the deep traps as well for the prolonged afterglow.
基金financially supported by National Key Research and Development Program of China(No.2022YFE0202400)the National Natural Science Foundation of China(No.22379103)+2 种基金Natural Science Foundation of Guangdong Province of China(No.2021A1515010388)the Science and Technology Projects of Suzhou City(No.SYC2022043)the Qing Lan Project of Jiangsu Province(2022)。
文摘The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.
基金the financial support from the National Natural Science Foundation of China(51972156,52072378,52102054 and 51927803)the National Key R&D Program of China(2022YFB3803400,2021YFB3800301)+2 种基金the Shenyang Science and Technology Program(22-322-3-19)the Youth Fund of the Education Department of Liaoning Province(LJKQZ20222324)the Outstanding Youth Fund of University of Science and Technology Liaoning(2023YQ11).
文摘Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.
基金the financial supports from the National Natural Science Foundation of China(Grant Nos.51872005,U1508201,52072002)。
文摘Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.
基金financially supported by the National Science Foundation of China(Grant No.11804106)。
文摘Although CoO is a promising electrode material for supercapacitors due to its high theoretical capacitance,the practical applications still suffering from inferior electrochemical activity owing to its low electrical conductivity,poor structural stability and inefficient nanostructure.Herein,we report a novel Cu0/Cu+co-doped CoO composite with adjustable metallic Cu0 and ion Cu+via a facile strategy.Through interior(Cu+)and exterior(Cu0)decoration of CoO,the electrochemical performance of CoO electrode has been significantly improved due to both the beneficial flower-like nanostructure and the synergetic effect of Cu0/Cu+co-doping,which results in a significantly enhanced specific capacitance(695 F g^(-1) at 1 A g^(-1))and high cyclic stability(93.4%retention over 10,000 cycles)than pristine CoO.Furthermore,this co-doping strategy is also applicable to other transition metal oxide(NiO)with enhanced electrochemical performance.In addition,an asymmetric hybrid supercapacitor was assembled using the Cu0/Cu+co-doped CoO electrode and active carbon,which delivers a remarkable maximal energy density(35 Wh kg^(-1)),exceptional power density(16 kW kg^(-1))and ultralong cycle life(91.5%retention over 10,000 cycles).Theoretical calculations further verify that the co-doping of Cu^(0)/Cu^(+)can tune the electronic structure of CoO and improve the conductivity and electron transport.This study demonstrates a facile and favorable strategy to enhance the electrochemical performance of transition metal oxide electrode materials.
基金Program for Changjiang Scholars and Innovative Research Team in University (IRT0730)the Key Project of Department of Science and Technology of Jiangxi ProvinceProject of Education Department of Jiangxi
文摘Green light-emitting Ba2SiO4：Eu^2＋ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere（a mixture of 5% H2 and 95% N2）.The results showed that the co-doping of La and Y could greatly enhance the fluorescence intensity of Ba2SiO4：Eu2＋ phosphors.The optimum doping concentration expressed by the x value in（Ba0.985-1.5xREx）2SiO4：0.03Eu^2＋（RE=La or Y） was determined to be of 0.05.The excitation and emission peaks of all as-synthesized phosphors were wide bands.The excitation bands ranged from 250 to 400 nm, which matched well with the wavelength of near ultraviolet white light-emitting diodes（LED） chip and could be used as a potential candidate for the fabrication of white LED.The emission bands from 450 to 550 nm were typical 5d-4f transition emission of Eu^2＋ and displayed un-symmetry profiles because of the two substitution sites of Ba^2＋ with Eu^2＋.
基金Project supported by the National Natural Science Foundation of China(51901089,52061015)Young Elite Scientists Sponsorship Program by CAST(YESS20200250)+3 种基金Young Talents Program of Jiangxi Provincial Major Discipline Academic and Technical Leaders Training Program(20212BCJ23008)China Postdoctoral Science Foundation(2020M682064)Postdoctoral Science foundation of Jiangxi Province(2020KY19)Technology Program of Fujian Province(2020H6201,2021T3063)。
文摘It is well known that Tb substitution for(Pr,Nd)in(Pr,Nd)-Fe-B based sintered magnetic materials is an effective way to increase intrinsic coercivity,but it is not quite clear whether the increment depends on the different matrix phases with various doping ingredient or not,which is essential to develop high quality magnets with high coercivity more efficiently and effectively with economic consumption of expensive Tb and other costly heavy rare earths.In this paper,we investigated the efficiency of Tb substitution for magnetic property in(Pr,Nd)-Fe-B sintered permanent magnets by co-doping Ga and Cu elements.It is shown that Ga and Cu co-doping can effectively improve the efficiency of Tb substitution to increase the thermal stability and the coercivity.The intrinsic coercivity increases up to 549 and 987 kA/m respectively by 1.5 wt%and 3.0 wt%Tb substitution in Ga and Cu co-doped magnets while the intrinsic coercivity increases up to only 334 and 613 kA/m respectively by the same amounts of Tb substitution in non-Ga and low-Cu magnets.In other words,it demonstrates that there is about 329-366 kA/m linear equivalent enhancement of intrinsic coercivity by 1.0 wt%Tb substitution for(Pr,Nd)in Ga and Cu co-doped magnets.The temperature coefficients of both intrinsic coercivityβand remanenceαat 20-150℃by 3.0 wt%Tb substitution for the magnets with Ga and Cu co-doping are-0.47%/K and-0.109%/K respectively,and in contrast those values are-0.52%/K and 0.116%/K respectively for the non-Ga and low-Cu magnets.It is the principal reason for more efficient enhancement of magnetic property by Tb substitution in the Ga and Cu co-doped magnets in which Tb atoms are expelled from triple junction phases(TJPs)to penetrate into the grain boundary phases(GB phases)and thus modify the grain boundary.It is prospected that the efficiency of Tb substitution would rely on different matrix phases with various doping constituents.
基金supported by Erasmus Mundus(BMUMID2011238)Moldavian Academy of Science(11.817.05.11F)Jenny and AnttiWihuri Foundation
文摘The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, were studied within the temperature interval of 6–300 K. At the 6 K temperature in the visible spectral range 2 bands were observed： a band in the excitonic spectral region and a band of self-activated luminescence. It was shown that co-doping of zinc selenide crystals with the chromium and ytterbium led to the combination of the impurities influence on the photoluminescent properties. At the liquid helium temperature in the middle infrared range of the spectra of the ytterbium and chromium co-doped crystal a band with the maximum localized at 1.7μm was observed, which was overlapped with a complex band in the middle-IR spectral range, characteristic for the chromium doped ZnSe crystals. On the basis of obtained data an interaction mechanism of the chromium and ytterbium co-doping impurities was proposed. Guided by the existent model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made. It was assumed that the resonant energy transfer from one chromium ion to another,which led to the concentration quenching of the IR emission in the ZnSe：Cr PL spectra, would lead to the broadening of the IR emission in the spectra of ytterbium and chromium co-doped zinc selenide crystals.g
文摘The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the density functional theory. The calculated results show that the carrier concentration is increased in the ZnO crystal codoped by N and Ag, and the codoped structure is stable and is more in favour of the formation of p-type ZnO.
基金supported by the National Natural Science Foundation of China(22075170,52072233)the Beijing National Laboratory for Condensed Matter Physics。
文摘Layered LiCoO_(2)(LCO)acts as a dominant cathode material for lithium-ion batteries(LIBs)in 3C products because of its high compacted density and volumetric energy density.Although improving the high cutoff voltage is an effective strategy to increase its capacity,such behavior would trigger rapid capacity decay due to the surface or/and structure degradation.Herein,we propose a bi-functional surface strategy involving constructing a robust spinel-like phase coating layer with great integrity and compatibility to LiCoO_(2) and modulating crystal lattice by anion and cation gradient co-doping at the subsurface.As a result,the modified LiCoO_(2)(AFM-LCO)shows a capacity retention of 80.9%after 500 cycles between 3.0and 4.6 V.The Al,F,Mg enriched spinel-like phase coating layer serves as a robust physical barrier to effectively inhibit the undesired side reactions between the electrolyte and the cathode.Meanwhile,the Al,F,Mg gradient co-doping significantly enhances the surficial structure stability,suppresses Co dissolution and oxygen release,providing a stable path for Li-ions mobility all through the long-term cycles.Thus,the surface bi-functional strategy is an effective method to synergistically improve the electrochemical performances of LCO at a high cut-off voltage of 4.6 V.
基金Project supported by the National Natural Science Foundation of China(51102073)the Natural Science Foundation of Education Department of Anhui Province of China(KJ2015A232,KJ2015B1105906)+3 种基金the Natural Science Foundation of Anhui Province of China(1308085QB35)the research fund of State Key Laboratory of Structural Chemistry(20110012)Anhui Province Outstanding Young Teachers Visit Abroad Training Projects(gxfxZD2016220)the Outstanding Young Talent Project in Colleges and Universities of Anhui Province
文摘Mn-Zn ferrites doped with different contents of Sm^（3＋） and Gd^（3＋） ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy（FTIR）, thermogravimetric analysis（TG）, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and vibrating sample magnetometer（VSM）. When samples were calcined in a relatively low temperature below 1100 °C, secondary phases（α-Fe_2O_3） could be identified. Therefore, in order to acquire pure and better crystallinity, the suitable calcining temperature of powders was selected at 1200 °C. It was also found that all the samples consisting of ferrite phases of typical spinel cubic structure and average crystallite sizes between 31.5 and 38.2 nm were obtained after calcining at 1200 oC for 4 h. The lattice parameters increased almost linearly with increasing Sm content. A dense microstructure was obtained after sintering at 1250 °C for 4 h. Through the analysis of magnetic properties, hysteresis loops for all the samples were narrow with low values of coercivity and retentivity, indicating the paramagnetic nature of these samples. And saturation magnetization Ms strongly depended on the type of additive to reach a maximum of 47.99 emu/g for x=0.015, which showed a great promise for hyperthermia applications.
基金supported by the National Natural Science Foundation of China(21573255,21573062)Natural Science Foundation of Liao Ning Province(20180510014)+1 种基金supported by Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science and the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)supported by the Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund(the second phase)under Grant No.U1501501。
文摘Electrochemical reduction of CO_(2)(CERR)to value-added chemicals is an attractive strategy for greenhouse gas mitigation,and carbon recycles utilization.Conventional metal catalysts suffered from low durability and sluggish kinetics impede the practical application.On the other hand,doped carbon materials recently demonstrate superior catalytic performance in CERR,which shows the potential to diminish the problems of metal catalysts to some extent.Herein,we present the design and fabrication of nitrogen(N),phosphorus(P)co-doped metal-free carbon materials as an efficient and stable electrocatalyst for reduction of CO_(2) to CO,which exhibits an excellent performance with a high faradaic efficiency of 92%(-0.55 V vs.RHE)and up to 24 h stability.A series of characterizations including TEM and XPS verified that nitrogen and phosphorous are successfully incorporated into the carbon matrix.Moreover,the comparisons between co-doping and single doping catalysts reveal that co-doping can significantly increase CERR performance.The improved catalytic activity is attributed to the synergetic effects between nitrogen and phosphorous dopants,which effectively modulate properties of the active site.The density functional theory(DFT)calculations were also performed to understand the synergy effects of dopants.It is revealed that the phosphorous doping can significantly lower the Gibbs free energy of COOH^(*)formation.Moreover,the introduction of the second dopants phosphorous can reduce the reaction barrier along the reaction path and cause polarization of density of states at the Fermi level.These changes can greatly enhance the activity of the catalysts.From a combined experimental and computational exploration,current work provides valuable insights into the reaction mechanism of CERR on N,P co-doped carbon catalysts,and the influence from synergy effects between dopants,which paves the way for the rational design of novel metal-free catalysts for CO2 electro-reduction.
基金financially supported by the National Natural Science Foundation of China(Project numbers.51834004,51774076,51704062)the Fundamental Research Funds for the Central Universities(N2025019)。
文摘The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.
基金We gratefully acknowledge financial supports from the National Natural Science Foundation of China(No.52202371,51905125,52102364)the Natural Science Foundation of Shandong Province(No.ZR2020QE066)+2 种基金Opening Project of State Key Laboratory of Advanced Technology for Float Glass(No.2020KF08)SDUT&Zibo City Integration Development Project(No.2021SNPT0045)the fellowship of China Postdoctoral Science Foundation(No.2020M672081).
文摘Biomass-derived carbon has demonstrated great potentials as advanced electrode for capacitive deionization(CDI),owing to good electroconductivity,easy availability,intrinsic pores/channels.However,conventional simple pyrolysis of biomass always generates inadequate porosity with limited surface area.Moreover,biomass-derived carbon also suffers from poor wettability and single physical adsorption of ions,resulting in limited desalination performance.Herein,pore structure optimization and element co-doping are integrated on banana peels(BP)-derived carbon to construct hierarchically porous and B,N co-doped carbon with large ions-accessible surface area.A unique expansionactivation(EA)strategy is proposed to modulate the porosity and specific surface area of carbon.Furthermore,B,N co-doping could increase the ions-accessible sites with improved hydrophilicity,and promote ions adsorption.Benefitting from the synergistic effect of hierarchical porosity and B,N co-doping,the resultant electrode manifest enhanced CDI performance for NaCl with large desalination capacity(29.5 mg g^(-1)),high salt adsorption rate(6.2 mg g^(-1)min^(-1)),and versatile adsorption ability for other salts.Density functional theory reveals the enhanced deionization mechanism by pore and B,N co-doping.This work proposes a facile EA strategy for pore structure modulation of biomass-derived carbon,and demonstrates great potentials of integrating pore and heteroatoms-doping on constructing high-performance CDI electrode.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10325415 and 50504017)the Natural Science Foundation of Hunan Province,China(Grant No.07JJ3102)+1 种基金the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.10C1171)the Science Development Foundation of Central South University,China(Grant Nos.08SDF02 and 09SDF09)
文摘Using the first-principles calculations, we investigate the electronic band structure and the quantum transport properties of metallic carbon nanotubes （MCNTs） with B/N pair co-doping. The results about formation energy show that the B/N pair co-doping configuration is a most stable structure. We find that the electronic structure and the transport properties are very sensitive to the doping concentration of the B/N pairs in MCNTs, where the energy gaps increase with doping concentration increasing both along the tube axis and around the tube, because the mirror symmetry of MCNT is broken by doping B/N pairs. In addition, we discuss conductance dips of the transmission spectrum of doped MCNTs. These unconventional doping effects could be used to design novel nanoelectronic devices.
基金supported by the National Natural Science Foundation of China(91834301)the Innovation Program of Shanghai Municipal Education Commission+1 种基金the Shanghai Scientific and Technological Innovation Project(18JC1410500)the Fundamental Research Funds for the Central Universities(222201718002)。
文摘The Ni-ultrahigh cathode material is one of the best choices for further increasing energy-density of lithium-ion batteries(LIBs),but they generally suffer from the poor structure stability and rapid capacity fade.Herein,the tungsten and phosphate polyanion co-doped LiNi_(0.9)Co_(0.1)O_(2)cathode materials are successfully fabricated in terms of Li(Ni_(0.9)Co_(0.7))_(1-x)W_(x)O_(2-4y)(PO_(4))_(y) by the precursor modification and subsequent annealing.The higher bonding energy of W—O(672 kJ·mol^(-1))can extremely stabilize the lattice oxygen of Ni-rich oxides compared with Ni—O(391.6 kJ·mol^(-1))and Co—O(368 kJ·mol^(-1)).Meanwhile,the stronger bonding of Ni—(PO_(4)^(3-))vs.Ni—O could fix Ni cations in the transition metal layer,and hence suppressing the Li/Ni disorder during the charge/discharge process.Therefore,the optimized Li(Ni_(0.9)Co_(0.1))_(0.99)W_(0.01)O_(1.96)(PO_4)_(0.01)delivers a remarkably extended cycling life with 95.1%retention of its initial capacity of 207.4 mA·h·g^(-1)at 0.2 C after 200 cycles.Meantime,the heteroatoms doping does not sacrifice the specific capacity even at different rates.
基金supported by National Natural Science Foundation of China(12175130,11875187)the Opening Project of State Key Laboratory of Key Laboratory of Transparent Opto-functional Inorganic Materials,Chinese Academy of Sciences(KLTOIM202002)。
文摘In this paper,effect of two strategies on afterglow behavior of Lu_(2)O_(3):Eu single crystal scintillato r,Pr^(3+)codoping and solid solution with Sc_(2)O_(3),were studied systematically.Two groups of Lu_(2)O_(3):5 at%Eu,x at%Pr(x=0,0.2,0.5,1,2 and 5)and(Lu1-yScy)_(2)O_(3):5 at%Eu(y=0,20 at%,50 at%and 70 at%)single crystals were grown by floating zone(FZ)method in air atmosphere.The structures of as-grown crystals were determined by X-ray diffraction(XRD).The scintillation,photoluminescence properties and carrier trap states were investigated through afterglow,X-ray excitation luminescence(XEL),transmittance,photoluminescence excitation(PLE)and photoluminescence(PL),PL decay and thermal stimulated luminescence(TSL)curves.It is found that with the increase of Pr^(3+)concentration,the afterglow level of the system decreases at the expense of scintillation luminescence efficiency.Meanwhile,although Sc_(2)O_(3):Eu presents much lower afterglow intensity than Lu_(2)O_(3):Eu,the addition of Sc_(2)O_(3)will just increase the afterglow level of the(Lu1-yScy)_(2)O_(3):5 at%Eu single crystal system.Possible mechanisms for above phenomena are discussed based on experimental results.
基金supported by CNPC safety and environmental protection key technology research and promotion project (No. 2017D-4613)Sub project of national science and technology major project (No. 2016ZX05040-003)China University of Petroleum (East China) Graduate Innovative Engineering Project (No. YCX2020039)。
文摘High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrothermal method for the first time.After doping,the tex ture of nanosphere becomes loose,the nanometer diameter is reduced,making the specific surface area of catalyst increased from 34.73 to 101.59 m^(2)/g.The characterization results show that more ZnS (111) crystal planes are exposed by N/Cu co-doping;the calculations of density functional theory show that N/Cu co-doping can increase the catalytic activity of the ZnS (111) crystal plane,enhance the adsorption capacity of (111) crystal plane to O_(2)and promote the generation of·O_(2)-.The energy levels of the introduced impurities can be hybridized with the energy levels of S and Zn at the top of valence band and the bottom o conduction band,which makes the band gap narrower,thus enhancing the absorption o visible light.Compared with pure ZnS,the degradation rates of 2,4-dichlorophenol (2,4-DCP and tetracycline (TC) by N/Cu-ZnS under visible light (>420 nm) are increased by 83.7 and51 times,respectively.In this research,a promising photocatalyst for photocatalytic degra dation of organic pollutants in wastewater is provided.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0205704 and 2018YFB2200101)the National Natural Science Foundation of China(Grant Nos.91964107 and 61774133)+2 种基金Fundamental Research Funds for the Central Universities,China(Grant No.2018XZZX003-02)the National Natural Science Foundation of China for Innovative Research Groups(Grant No.61721005)Zhejiang University Education Foundation Global Partnership Fund。
文摘The p-type doping efficiency of 4 H silicon carbide(4 H-SiC)is rather low due to the large ionization energies of p-type dopants.Such an issue impedes the exploration of the full advantage of 4 H-SiC for semiconductor devices.In this study,we show that co-doping group-IVB elements effectively decreases the ionization energy of the most widely used p-type dopant,i.e.,aluminum(Al),through the defect-level repulsion between the energy levels of group-IVB elements and that of Al in 4 H-SiC.Among group-IVB elements Ti has the most prominent effectiveness.Ti decreases the ionization energy of Al by nearly 50%,leading to a value as low as~0.13 eV.As a result,the ionization rate of Al with Ti co-doping is up to~5 times larger than that without co-doping at room temperature when the doping concentration is up to 10^(18)cm^(-3).This work may encourage the experimental co-doping of group-IVB elements such as Ti and Al to significantly improve the p-type doping efficiency of 4 H-SiC.
