Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(...Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.展开更多
Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure C...Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure CeO2 were prepared by CTAB-assisted hydrothermal method for CO oxidation.XRD,SEM,EDS,BET,Raman,H2-TPR,XPS and in situ DRIFTS techniques were carried out to study the physicochemical properties and to correlate them to the activity.The doped samples maintain the cubic fluorite structure of CeO2 with high crystallinity and small crystallite size,forming Ce-based solid solutions.The obtained catalysts have large mesoporous structure with average pore size of 10-14 nm.The doped transition metal enhances the oxygen vacancies and improves reducibility of the solids.The synergistic interaction of Mn and Cu codoping induces mo re oxygen vacancies,pro moting the increase of surface adsorbed oxygen and the transfer of bulk oxygen of catalyst,thereby enhancing the catalytic activity for CO oxidation.Besides,the decomposition rate of the carbonate species which is derived from in situ DRIFTS for each catalyst can provide a measure to evaluate its catalytic activity of CO oxidation.展开更多
Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous c...Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous carbons(NOPCs) are fabricated based on a simple Schiff-base reaction between m-phenylenediamine and terephthalaldehyde.The NOPCs have tunable morphologies,high surface areas,abundant heteroatom doping.More importantly,the carbons show a dominant micropores of 0.5-0.8 nm,comparable to the ionic sizes of LiTFSI(Li^+0.069 nm;TFSI-0.79 nm) water-in-salt electrolyte with a high potential window of 2.2 V.Consequently,the fabricated symmetric supercapacitor gives a high energy output of 30.5 Wh/kg at 1 kW/kg,and high stability after successive 10,000 cycles with ^96.8% retention.This study provides promising potential to develop high-energy supercapacitors.展开更多
A series of La/Ce-codoped Bi2O3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N2...A series of La/Ce-codoped Bi2O3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N2 physical adsorption, X-ray powder diffraction（XRD）, scanning electron microscope（SEM）, transmission electron microscope（TEM）, UV–Vis diffuse reflectance（UV–Vis DRS）, Fourier transform infrared spectroscopy（FT-IR）,photoelectrochemical measurements, and photoluminescence（PL） spectroscopy. The characterization results indicated that La and Ce doping induced obvious crystal phase transformation in Bi2O3, from monoclinic to tetragonal phase. La and Ce codoping also gave rise to the obvious synergetic effects, e.g., the lattice contraction of Bi2O3, the decrease of crystal size and the increase of surface area. The photocatalytic performance of the prepared catalysts was evaluated by removal of dye acid orange II with high concentration under visible light irradiation. Results showed that La/Ce-codoped Bi2O3 displayed much higher photocatalytic performance than that of bare Bi2O3, single La or Ce doped Bi2O3 samples. The superior photocatalytic activity was mainly attributed to the improved texture and surface properties and the synergistic effects of La and Ce codoping on suppressing the recombination of photo-generated electrons（e^-） and holes（h~＋）.展开更多
First-principles plane-wave pseudopotential calculations are performed to study the geometrical structures, for- mation energies, and electronic and optical properties of Y-doped, N-doped, and （Y, N）-codoped Ti02. T...First-principles plane-wave pseudopotential calculations are performed to study the geometrical structures, for- mation energies, and electronic and optical properties of Y-doped, N-doped, and （Y, N）-codoped Ti02. The calculated results show that Y and N codoping leads to lattice distortion, easier separation of photogenerated electron-hole pairs and band gap narrowing. The optical absorption spectra indicate that an obvious red-shift occurs upon Y and N codoping, which enhances visible-light photocatalytic activity.展开更多
La3+ was selected to elevate the lattice electronic conductivity of LiFePO4,and LiFePO4/(C+La3+) cathode powders were synthesized by microwave heating using a domestic microwave oven for 35 min. The microstructures an...La3+ was selected to elevate the lattice electronic conductivity of LiFePO4,and LiFePO4/(C+La3+) cathode powders were synthesized by microwave heating using a domestic microwave oven for 35 min. The microstructures and morphologies of the synthesized materials were investigated by XRD and SEM. The electrochemical performances were evaluated by galvanostatic charge-discharge. The electrochemical performance of LiFePO4 with different La3+ contents was studied. Results indicated that the initial specific disch...展开更多
Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were...Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. In comparison with the as-made precursor, significant enhancement of upconversion luminescence was observed in the Er3+/Yb3+ codoped oxyfluoride glass ceramics, which may be due to the variation of coordination environment around Er3+ and Yb3+ ions after crystallization. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and that of the blue upconversion luminescence was a three-photon process.展开更多
Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i...Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.展开更多
The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattic...The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.展开更多
The crystal structures, electronic structures and optical properties of nitrogen or/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on...The crystal structures, electronic structures and optical properties of nitrogen or/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density functional theory. Highly efficient visible-light-induced nitrogen or/and praseodymium doped anatase TiO2 nanocrystal photocatalyst were synthesized by a microwave chemical method. The calculated results show that the photocatalytic activity of TiO2 can be enhanced by N doping or Pr doping, and can be further enhanced by N＋Pr codoping. The band gap change of the codoping TiO2 is more obvious than that of the single ion doping, which results in the red shift of the optical absorption edges. The results are of great significance for the understanding and further development of visible-light response high activity modified TiO2 photocatalyst. The photocatalytic activity of the samples for methyl blue degradation was investigated under the irradiation of fluorescent light. The experimental results show that the codoping TiO2 photocatalytic activity is obviously higher than that of the single ion doping. The experimental results accord with the calculated results.展开更多
Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence c...Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and near infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm^3＋： ^1D2 →^3F4, ^1G4 →^3H6, ^1G4 →^3F4, and ^3H4 →^3H6, respectively, are observed. Due to the sensitization of Yb^3＋ ions, all the upconversion luminescence intensities are enhanced considerably with Yb^3＋ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.展开更多
The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferro...The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferromagnetic（AFM） state.Compared to the Cu doped system,the ionicities of C–Cu and C–Si in Cu and N codoped Si C are respectively enhanced and weakened.Especially,the Cu and N codoped Si C systems favor the ferromagnetic（FM） coupling.The FM interactions can be explained by virtual hopping.However,higher N concentration will weaken the ferromagnetism.In order to keep the FM interaction,the N concentration should be restricted within 9.3% according to our analysis.展开更多
Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffractio...Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in ZnO and the evaporation of Li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.展开更多
The solid acid catalyst, N-F codoped Ti O2/Si O2 composite oxide was prepared by a sol-gel method using NH4 F as nitrogen and fluorine source. The prepared materials were characterized by X-ray diffraction（XRD）, sca...The solid acid catalyst, N-F codoped Ti O2/Si O2 composite oxide was prepared by a sol-gel method using NH4 F as nitrogen and fluorine source. The prepared materials were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS）, UV-Visible diffuse reflectance spectroscopy（UV-Vis）,ammonia adsorption and temperature-programmed desorption（NH3-TPD）, in situ Fourier transform infrared spectroscopy（FT-IR） and N2 physical adsorption isotherm. The photocatalytic activity of the catalyst for acrylonitrile degradation was investigated under simulant solar irradiation. The results showed that strong Lewis and Brnsted acid sites appear on the surface of the sample after N-F doping. Systematic investigation showed that the highest photocatalytic activity for acrylonitrile degradation was obtained for samples calcined at 450°C with molar ratio（NH4F to Ti） of 0.8. The degradation ratio of 71.5% was achieved with the prepared catalyst after 6-min irradiation, demonstrating the effectiveness of photocatalytic degradation of acrylonitrile with N-F codoped Ti O2/Si O2 composite oxide. The photocatalyst is promising for application under solar light irradiation.Moreover, the intermediates generated after irradiation were verified by gas chromatography-mass spectrometry（GC-MS） analysis and UV-Vis spectroscopy to be simple organic acids with lower toxicity, and the degradation pathway was also proposed for acrylonitrile degradation with the prepared catalyst.展开更多
Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the rem...Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction.The mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and precipitation.In addition to precipitation and complexation,the elimination mechanism of Pb(Ⅱ) also contained ion exchange and electrostatic interactions.Competitive and synergistic effects existed simultaneously in the co-contamination system.The suppression of As(Ⅲ) was ascribed to competitive complexation of the two metals on Fe/S-BC,while the synergy of Pb(Ⅱ) was attributed to the formation of the PbFe2(AsO_(4))2(OH)2.Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(Ⅲ) and Pb(Ⅱ),regardless of pH dependency and interference by various coexisting ions.The maximum adsorption capacities of the Fe/S-BC for As(Ⅲ) and Pb(Ⅱ) were 91.2 mg/g and 631.7 mg/g,respectively.Fe/S-BC could be treated as a novel candidate for the elimination of As(Ⅲ)-Pb(Ⅱ) combined pollution.展开更多
Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amo...Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amounts of ionic liquid on the structural,optical and photocatalytic properties of the samples were investigated.Characterization results show that more compact interlayer sacking can be achieved by post‐thermal treatment.Combined with C‐I codoping by insertion of ionic liquids,much enlarged surface area but optimized sp2 conjugated heterocyclic structure can be found in the catalysts.Optical and energy band analysis results evidence that the light absorptions especially in visible light region are significantly improved.Although the band gap of porous C‐I codoped samples enlarge because of the generation of porous,the negatively shifted conduction band position thermodynamically supplies stronger motivation for water reduction.Photoelectricity tests reveal that the photo‐induced electron density was increased after C‐I codoping modification.Also,the recombination rate of electron‐hole pairs is remarkably inhibited.The catalysts with moderate C‐I codoing content perform sharply enhanced photocatalytic H2 evolution activity under visible light irradiation.A H2 evolution rate of 168.2μmol/h was achieved and it was more than 9.8 times higher than pristine carbon nitride.This study demonstrates a novel non‐metal doping strategy for synthesis and optimization of polymer semiconductor with gratifying photocatalytic H2 evolution performance from water hydrolysis.展开更多
Ce and C-S codoped mesoporous TiO_(2)nanocomposites were synthesized via a sol-gel method integrated with an evaporation-induced self-assembly approach.The basic physicochemical characteristics of the synthetic sample...Ce and C-S codoped mesoporous TiO_(2)nanocomposites were synthesized via a sol-gel method integrated with an evaporation-induced self-assembly approach.The basic physicochemical characteristics of the synthetic samples were analyzed via a series of characterization techniques.The results reveal that C-S and Ce codoping on mesoporous TiO_(2)enhances the photocatalytic activity owing to the synergistic effect caused by narrowing the band gap,enhancing adsorption,trapping and transferring the excited e^(-)/h^(+)pairs and suppressing the recombination of e^(-)/h^(+)pairs.Furthermore,the obtained C,S-TiO_(2)/CeO_(2)materials exhibit large specific surface areas and numerous pores which not only effectively improve the adsorption-enrichment capability,but also supply multi-dimensional mass and electron transfer channels.The photodegradation efficiency of RhB by C,S-TiO_(2)/CeO_(2)within 40 min is nearly 100%,and its degradation efficiency is 6.63 times that of undoped TiO_(2).Recycling experiments show that mesoporous C,S-TiO_(2)/CeO_(2)shows excellent recoverability and stability.Furthermore,by trapping experiments,·O_(2)e^(-)/h^(+)and·OH are the predominant active species and a possible reaction mechanism is proposed.展开更多
Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require comple...Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors,is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon,which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory(DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.展开更多
Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants.Herein,a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporo...Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants.Herein,a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporous(Co/N-MCs)was applied as an adsorbent for tetracycline removal.Taking integrated advantages of ordered mesopores on carbon-based structures and N-doping inducing the strengthenedπ–πdispersion and generation of pyridinic N,as well as cobaltic nanoparticles embedded in carbon nanoplates,the Co/N-MCs was tailored for high efficiently absorbing tetracycline viaπ-πinteraction,Lewis acid-base interaction,metal complexation and electrostatic attraction.The Co/N-MCs had the advantages of high surface area,porous structure,plenty adsorption sites,and easy separation.As such,the as-prepared Co/N-MCs adsorbents significantly enhanced tetracycline removal performance with a maximum adsorption capacity of 344.83 mg·g^(-1) at pH 6 and good reusability,which was finally applied to removal tetracycline from tap water sample.Furthermore,the adsorption process towards tetracycline hydrochloride could be well attributed to the pseudo-second-order kinetic and Langmuir isotherm models.Compared with traditional carbon-based adsorbents,it owns a simpler synthesis method and a higher adsorption capacity,as well as it is a promising candidate for water purification.展开更多
Rational regulation of stable graphitic carbon nitride(CN)for superior peroxymonosulfate(PMS)activation is important in the catalytic degradation of water contaminants.In this work,the copper oxide and oxygen co-doped...Rational regulation of stable graphitic carbon nitride(CN)for superior peroxymonosulfate(PMS)activation is important in the catalytic degradation of water contaminants.In this work,the copper oxide and oxygen co-doped graphitic carbon nitride(Cu O/O-CN)was prepared via one-step synthesis and applied in activating PMS for oxytetracycline(OTC)degradation,displaying superior catalytic performance.Systematic characterization and theoretical calculations indicated that the synergistic effect between the oxygen site of CN and CuO can modulate the electronic structure of the whole composite further facilitating the formation of non-radical^(1)O_(2)and various reactive radicals.Results of the influencing factor experiments revealed that CuO/O-CN has a strong resistance to the environmental impact.The degradation efficiency of OTC in the real water environment even exceeded that in the deionized water.After four successive runs of the optimal catalyst,the OTC removal rate was still as high as 91.3%.This work developed a high-efficiency PMS activator to remove refractory pollutants via both radical pathway and non-radical pathway,which showed a promising potential in the treatment of wastewaters.展开更多
基金Project supported by the National Natural Science Foundation of China(61805134,11974229,22303044)Fundamental Research Program of Shanxi Province(202203021221121)+3 种基金China Postdoctoral Science Foundation(2022M711898)Natural Science Fo undation of Shandong Province(ZR2023QB135)Postdoctoral Innovation Project of Shandong Province(SDCX-ZG-202201004)Graduate Innovation Project in Shanxi Province(2024KY450)。
文摘Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.
基金Project supported by the National Natural Science Foundation of China(21777055)Shandong Provincial Natural Science Foundation(ZR2017BB004)+1 种基金Shandong Province Key Research and Development Plan(2017GGX202004)Shandong Province Major Science and Technology Innovation Project(2017CXGC1004)
文摘Codoping approach is an appealing strategy to further improve the catalytic activity of Ce-based catalysts.In the present study,Mn and/or Cu doped ceria solid solutions MnxCuyCe1-x-yO2,CuxCe1-xO2,MnxCe1-xO2 and pure CeO2 were prepared by CTAB-assisted hydrothermal method for CO oxidation.XRD,SEM,EDS,BET,Raman,H2-TPR,XPS and in situ DRIFTS techniques were carried out to study the physicochemical properties and to correlate them to the activity.The doped samples maintain the cubic fluorite structure of CeO2 with high crystallinity and small crystallite size,forming Ce-based solid solutions.The obtained catalysts have large mesoporous structure with average pore size of 10-14 nm.The doped transition metal enhances the oxygen vacancies and improves reducibility of the solids.The synergistic interaction of Mn and Cu codoping induces mo re oxygen vacancies,pro moting the increase of surface adsorbed oxygen and the transfer of bulk oxygen of catalyst,thereby enhancing the catalytic activity for CO oxidation.Besides,the decomposition rate of the carbonate species which is derived from in situ DRIFTS for each catalyst can provide a measure to evaluate its catalytic activity of CO oxidation.
基金financially supported by the National Natural Science Foundation of China(Nos.21875165,51772216 and 21703161)the Science and Technology Commission of Shanghai Municipality,China(No.14DZ2261100)the Fundamental Research Funds for the Central Universities。
文摘Pore size and distribution in carbon-based materials are regarded to be a key factor to affect the electrochemical capacitive performances of the resultant electrodes.In this study,nitrogen and oxygen codoped porous carbons(NOPCs) are fabricated based on a simple Schiff-base reaction between m-phenylenediamine and terephthalaldehyde.The NOPCs have tunable morphologies,high surface areas,abundant heteroatom doping.More importantly,the carbons show a dominant micropores of 0.5-0.8 nm,comparable to the ionic sizes of LiTFSI(Li^+0.069 nm;TFSI-0.79 nm) water-in-salt electrolyte with a high potential window of 2.2 V.Consequently,the fabricated symmetric supercapacitor gives a high energy output of 30.5 Wh/kg at 1 kW/kg,and high stability after successive 10,000 cycles with ^96.8% retention.This study provides promising potential to develop high-energy supercapacitors.
基金supported by the National Natural Science Foundation of China (Nos. 21567008, 21607064, 21263005)the Natural Science Foundation of Jiangxi Province (No. 20161BAB203090)the Program of Qingjiang Excellent Young Talents, Jiangxi University of Science and Technology,the Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province China (No. KJLD14046)
文摘A series of La/Ce-codoped Bi2O3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N2 physical adsorption, X-ray powder diffraction（XRD）, scanning electron microscope（SEM）, transmission electron microscope（TEM）, UV–Vis diffuse reflectance（UV–Vis DRS）, Fourier transform infrared spectroscopy（FT-IR）,photoelectrochemical measurements, and photoluminescence（PL） spectroscopy. The characterization results indicated that La and Ce doping induced obvious crystal phase transformation in Bi2O3, from monoclinic to tetragonal phase. La and Ce codoping also gave rise to the obvious synergetic effects, e.g., the lattice contraction of Bi2O3, the decrease of crystal size and the increase of surface area. The photocatalytic performance of the prepared catalysts was evaluated by removal of dye acid orange II with high concentration under visible light irradiation. Results showed that La/Ce-codoped Bi2O3 displayed much higher photocatalytic performance than that of bare Bi2O3, single La or Ce doped Bi2O3 samples. The superior photocatalytic activity was mainly attributed to the improved texture and surface properties and the synergistic effects of La and Ce codoping on suppressing the recombination of photo-generated electrons（e^-） and holes（h~＋）.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10647008, 50971099, and 21176199)the Research Fund for the Doctoral Program of Higher Education, China (Grant Nos. 20096101110017 and 20096101110013)+1 种基金the Key Project of the Natural Science Foundation of Shaanxi Province, China (Grant Nos. 2010JZ002 and 2011JM1001)the Graduate Innovation Fund of Northwest University, China (Grant No. 10YZZ38)
文摘First-principles plane-wave pseudopotential calculations are performed to study the geometrical structures, for- mation energies, and electronic and optical properties of Y-doped, N-doped, and （Y, N）-codoped Ti02. The calculated results show that Y and N codoping leads to lattice distortion, easier separation of photogenerated electron-hole pairs and band gap narrowing. The optical absorption spectra indicate that an obvious red-shift occurs upon Y and N codoping, which enhances visible-light photocatalytic activity.
基金the National Natural Science Foundation of China (No. 50872090)
文摘La3+ was selected to elevate the lattice electronic conductivity of LiFePO4,and LiFePO4/(C+La3+) cathode powders were synthesized by microwave heating using a domestic microwave oven for 35 min. The microstructures and morphologies of the synthesized materials were investigated by XRD and SEM. The electrochemical performances were evaluated by galvanostatic charge-discharge. The electrochemical performance of LiFePO4 with different La3+ contents was studied. Results indicated that the initial specific disch...
基金Project supported by China Postdoctoral Science Foundation funded project (20080430216)National Natural Science Foundation of China (60508014)+1 种基金Program for New Century Excellent Talents in University (NCET-07-0786)Zhejiang Provincial Natural Science Foundation of China (Z4100030)
文摘Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated. Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. In comparison with the as-made precursor, significant enhancement of upconversion luminescence was observed in the Er3+/Yb3+ codoped oxyfluoride glass ceramics, which may be due to the variation of coordination environment around Er3+ and Yb3+ ions after crystallization. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and that of the blue upconversion luminescence was a three-photon process.
基金This work was supported by the National Natural Sci- ence Foundation of China （No.11034006, No.21273208, and No.21473168）, the Anhui Provincial Natural Sci- ence Foundation （No.1408085QB26）, the hmdamental Research Funds for the Central Universities, the China Postdoctoral Science Foundation （No.2012M511409）, and the Supercomputing Center of Chinese Academy of Sciences, Shanghai and USTC Supercomputer Cen- ters.
文摘Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.
基金Natural Science Foundation of Shanxi Province(No.2009011014)
文摘The impact of N-and X（X=S,Se,Te）-codoping on electronic properties of anatase TiO2 has been systematically investigated using density functional theory （DFT）.The optimized geometry shows that there is large lattice expansion for the codoped anatase TiO2 due to large atomic radius of the codoped atom.The calculated substitution energies indicate that incorporation of X（X =S,Se,Te） into N-doped bulk TiO2 can not promote synergistic effect on N after substituting for Ti,whcreas it is bctter after substituting for O.According to the total density of states （DOS） and corresponding partial DOS （PDOS）,it can be seen that substituting X（X =S,Se,Te） for O,N 2p orbital is strongly hybridized with impurity states （S 3p,Se 4p,Te 5p）.After substituting X（X=S,Se,Te） for Ti,conduction band is mainly dominated by Ti 3d orbit and S 3p （Se 4p or Te 5p）-N 2p-Ti 3d hybridized states are formed.Based on Bader analysis,it can be indicated that the electron transfer is from N to X（X=S,Se,Te） if substituting X（X=S,Se,Te） for O,but it is opposite if substitute X（X=S,Se,Te） for Ti.
基金Project supported by the National Natural Science Foundation of China(Grant No.50862009)the New Century Excellent Talents in University of the Ministry of Education,China(Grant No.NCET-04-0915)the Natural Science Foundation of Yunnan Province of China(Grant No.2005E007M)
文摘The crystal structures, electronic structures and optical properties of nitrogen or/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density functional theory. Highly efficient visible-light-induced nitrogen or/and praseodymium doped anatase TiO2 nanocrystal photocatalyst were synthesized by a microwave chemical method. The calculated results show that the photocatalytic activity of TiO2 can be enhanced by N doping or Pr doping, and can be further enhanced by N＋Pr codoping. The band gap change of the codoping TiO2 is more obvious than that of the single ion doping, which results in the red shift of the optical absorption edges. The results are of great significance for the understanding and further development of visible-light response high activity modified TiO2 photocatalyst. The photocatalytic activity of the samples for methyl blue degradation was investigated under the irradiation of fluorescent light. The experimental results show that the codoping TiO2 photocatalytic activity is obviously higher than that of the single ion doping. The experimental results accord with the calculated results.
基金Project supported by the Shanghai ＂Post-Qi-Ming-Xing plan＂ for Young Scientists, China （Grant No 04QMX1448） and the National Natural Science Foundation of China （Grant No 60207006）.The author would like to thank Wen L,Shen Y H and Zhao Y for their help in machining and measuring.
文摘Novel oxyfluoride glasses are developed with the composition of 30SiO2-15Al2O3-28PbF2-22CdF2-0.1TmF3 - xYbF3 - （4.9 - x） AlF3（x=0, 0.5, 1.0, 1.5, 2.0） in tool fraction, Furthermore, the upconversion luminescence characteristics under a 970nm excitation are investigated. Intense blue, red and near infrared luminescences peaked at 453nm, 476nm, 647nm and 789nm, which correspond to the transitions of Tm^3＋： ^1D2 →^3F4, ^1G4 →^3H6, ^1G4 →^3F4, and ^3H4 →^3H6, respectively, are observed. Due to the sensitization of Yb^3＋ ions, all the upconversion luminescence intensities are enhanced considerably with Yb^3＋ concentration increasing. The upconversion mechanisms are discussed based on the energy matching rule and quadratic dependence on excitation power. The results indicate that the dominant mechanism is the excited state absorption for those upconversion emissions.
基金Project supported by the Higher School Science Research Outstanding Youth Fund Project of Ningxia,China(Grant No.NGY2015049)
文摘The electronic structures and magnetic properties of the Cu and N codoped 3C-Si C system have been investigated by the first-principles calculation.The results show that the Cu doped Si C system prefers the anti-ferromagnetic（AFM） state.Compared to the Cu doped system,the ionicities of C–Cu and C–Si in Cu and N codoped Si C are respectively enhanced and weakened.Especially,the Cu and N codoped Si C systems favor the ferromagnetic（FM） coupling.The FM interactions can be explained by virtual hopping.However,higher N concentration will weaken the ferromagnetism.In order to keep the FM interaction,the N concentration should be restricted within 9.3% according to our analysis.
基金supported by the National Basic Research Program of China under Grant No.2006CB604906the National Natural Science Foundation of China under Grant No.51072181the Doctoral Fund of Ministry of Education of China under Grant No.20060335087
文摘Effects of growth temperature on the structural and electrical properties of Li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in ZnO and the evaporation of Li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.
基金financially supported by the Science and Technology Innovation Commission of Shenzhen Municipality, China (No. JCYJ20120613154128107)
文摘The solid acid catalyst, N-F codoped Ti O2/Si O2 composite oxide was prepared by a sol-gel method using NH4 F as nitrogen and fluorine source. The prepared materials were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS）, UV-Visible diffuse reflectance spectroscopy（UV-Vis）,ammonia adsorption and temperature-programmed desorption（NH3-TPD）, in situ Fourier transform infrared spectroscopy（FT-IR） and N2 physical adsorption isotherm. The photocatalytic activity of the catalyst for acrylonitrile degradation was investigated under simulant solar irradiation. The results showed that strong Lewis and Brnsted acid sites appear on the surface of the sample after N-F doping. Systematic investigation showed that the highest photocatalytic activity for acrylonitrile degradation was obtained for samples calcined at 450°C with molar ratio（NH4F to Ti） of 0.8. The degradation ratio of 71.5% was achieved with the prepared catalyst after 6-min irradiation, demonstrating the effectiveness of photocatalytic degradation of acrylonitrile with N-F codoped Ti O2/Si O2 composite oxide. The photocatalyst is promising for application under solar light irradiation.Moreover, the intermediates generated after irradiation were verified by gas chromatography-mass spectrometry（GC-MS） analysis and UV-Vis spectroscopy to be simple organic acids with lower toxicity, and the degradation pathway was also proposed for acrylonitrile degradation with the prepared catalyst.
基金supported by the National Key Research and Development Program of China (No. 2018YFC1802803)the National Natural Science Foundation of China (No. 21677041)the Science and Technology Project of Guangzhou City, China (No. 202103000018)。
文摘Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction.The mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and precipitation.In addition to precipitation and complexation,the elimination mechanism of Pb(Ⅱ) also contained ion exchange and electrostatic interactions.Competitive and synergistic effects existed simultaneously in the co-contamination system.The suppression of As(Ⅲ) was ascribed to competitive complexation of the two metals on Fe/S-BC,while the synergy of Pb(Ⅱ) was attributed to the formation of the PbFe2(AsO_(4))2(OH)2.Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(Ⅲ) and Pb(Ⅱ),regardless of pH dependency and interference by various coexisting ions.The maximum adsorption capacities of the Fe/S-BC for As(Ⅲ) and Pb(Ⅱ) were 91.2 mg/g and 631.7 mg/g,respectively.Fe/S-BC could be treated as a novel candidate for the elimination of As(Ⅲ)-Pb(Ⅱ) combined pollution.
基金the National Natural Science Foundation of China(21503096,21407067)the Natural Science Foundation of Jiangsu Province(BK20140506)~~
文摘Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amounts of ionic liquid on the structural,optical and photocatalytic properties of the samples were investigated.Characterization results show that more compact interlayer sacking can be achieved by post‐thermal treatment.Combined with C‐I codoping by insertion of ionic liquids,much enlarged surface area but optimized sp2 conjugated heterocyclic structure can be found in the catalysts.Optical and energy band analysis results evidence that the light absorptions especially in visible light region are significantly improved.Although the band gap of porous C‐I codoped samples enlarge because of the generation of porous,the negatively shifted conduction band position thermodynamically supplies stronger motivation for water reduction.Photoelectricity tests reveal that the photo‐induced electron density was increased after C‐I codoping modification.Also,the recombination rate of electron‐hole pairs is remarkably inhibited.The catalysts with moderate C‐I codoing content perform sharply enhanced photocatalytic H2 evolution activity under visible light irradiation.A H2 evolution rate of 168.2μmol/h was achieved and it was more than 9.8 times higher than pristine carbon nitride.This study demonstrates a novel non‐metal doping strategy for synthesis and optimization of polymer semiconductor with gratifying photocatalytic H2 evolution performance from water hydrolysis.
基金Project supported by the National Natural Science Foundation of China(41831285,51974261)Doctoral Research Initiation Project(YBZ202127)from Xichang University。
文摘Ce and C-S codoped mesoporous TiO_(2)nanocomposites were synthesized via a sol-gel method integrated with an evaporation-induced self-assembly approach.The basic physicochemical characteristics of the synthetic samples were analyzed via a series of characterization techniques.The results reveal that C-S and Ce codoping on mesoporous TiO_(2)enhances the photocatalytic activity owing to the synergistic effect caused by narrowing the band gap,enhancing adsorption,trapping and transferring the excited e^(-)/h^(+)pairs and suppressing the recombination of e^(-)/h^(+)pairs.Furthermore,the obtained C,S-TiO_(2)/CeO_(2)materials exhibit large specific surface areas and numerous pores which not only effectively improve the adsorption-enrichment capability,but also supply multi-dimensional mass and electron transfer channels.The photodegradation efficiency of RhB by C,S-TiO_(2)/CeO_(2)within 40 min is nearly 100%,and its degradation efficiency is 6.63 times that of undoped TiO_(2).Recycling experiments show that mesoporous C,S-TiO_(2)/CeO_(2)shows excellent recoverability and stability.Furthermore,by trapping experiments,·O_(2)e^(-)/h^(+)and·OH are the predominant active species and a possible reaction mechanism is proposed.
基金supported by the National Natural Science Foundation of China (31890771 and 31901249)the Young Elite Scientists Sponsorship Program by CAST (2019QNRC001)+3 种基金the Hunan Provincial Technical Innovation Platform and Talent Program in Science and Technology (2020RC3041)the Training Program for Excellent Young Innovators of Changsha (kq2106056)the Hunan Provincial Natural Science Foundation of China (2022JJ30079)the Postgraduate Technology Innovation Project of Central South University of Forestry and Technology (2022CX02017)。
文摘Carbon materials are effective substitutes for Pt counter electrodes(CEs) in dye-sensitized solar cells(DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors,is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon,which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory(DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.
基金financed by Grants from National Science Foundation of China(21675127,31901794)Chinese Universities Scientific Fund(2452018083)+3 种基金the National Postdoctoral Program for Innovative Talents(BX20180263)the Tang Scholar by Cyrus Tang Foundation,the Young Talent Fund of University Association for Science and Technology in Shaanxi,China(2019-02-03)the Development Project of Qinghai Provincial Key Laboratory(2017-ZJY10)the Key Research and Development Program of Shaanxi Province(2019NY-111)。
文摘Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants.Herein,a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporous(Co/N-MCs)was applied as an adsorbent for tetracycline removal.Taking integrated advantages of ordered mesopores on carbon-based structures and N-doping inducing the strengthenedπ–πdispersion and generation of pyridinic N,as well as cobaltic nanoparticles embedded in carbon nanoplates,the Co/N-MCs was tailored for high efficiently absorbing tetracycline viaπ-πinteraction,Lewis acid-base interaction,metal complexation and electrostatic attraction.The Co/N-MCs had the advantages of high surface area,porous structure,plenty adsorption sites,and easy separation.As such,the as-prepared Co/N-MCs adsorbents significantly enhanced tetracycline removal performance with a maximum adsorption capacity of 344.83 mg·g^(-1) at pH 6 and good reusability,which was finally applied to removal tetracycline from tap water sample.Furthermore,the adsorption process towards tetracycline hydrochloride could be well attributed to the pseudo-second-order kinetic and Langmuir isotherm models.Compared with traditional carbon-based adsorbents,it owns a simpler synthesis method and a higher adsorption capacity,as well as it is a promising candidate for water purification.
基金financially supported by the program for the National Natural Science Foundation of China(Nos.52170162,51809090,52100182,52100180)the Natural Science Foundation of Hunan Province,China(Nos.2022JJ10016,2019JJ50077,2021JJ40087)+4 种基金the Science and Technology Innovation Program of Hunan Province(No.2021RC3049)the Fundamental Research Funds for the Central Universities(No.531118010114)the China National Postdoctoral Program for Innovative Talents(No.BX20200119)the Project Funded by China Postdoctoral Science Foundation(No.2021M690961)the Fundamental Research Funds for the Central Universities(No.531118010114)。
文摘Rational regulation of stable graphitic carbon nitride(CN)for superior peroxymonosulfate(PMS)activation is important in the catalytic degradation of water contaminants.In this work,the copper oxide and oxygen co-doped graphitic carbon nitride(Cu O/O-CN)was prepared via one-step synthesis and applied in activating PMS for oxytetracycline(OTC)degradation,displaying superior catalytic performance.Systematic characterization and theoretical calculations indicated that the synergistic effect between the oxygen site of CN and CuO can modulate the electronic structure of the whole composite further facilitating the formation of non-radical^(1)O_(2)and various reactive radicals.Results of the influencing factor experiments revealed that CuO/O-CN has a strong resistance to the environmental impact.The degradation efficiency of OTC in the real water environment even exceeded that in the deionized water.After four successive runs of the optimal catalyst,the OTC removal rate was still as high as 91.3%.This work developed a high-efficiency PMS activator to remove refractory pollutants via both radical pathway and non-radical pathway,which showed a promising potential in the treatment of wastewaters.
