Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria.However,the residual norfloxacin in the environment can be biomagnified via food chain andmay damage the human liver and del...Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria.However,the residual norfloxacin in the environment can be biomagnified via food chain andmay damage the human liver and delay the bone development ofminors.Present work described a reliable and sensitive smartphone colorimetric sensing system based on cobaltdoped Fe_(3)O_(4) magnetic nanoparticles(Co-Fe_(3)O_(4) MNPs)for the visual detection of norfloxacin.Compared with Fe_(3)O_(4),Co-Fe_(3)O_(4) MNPs earned more remarkably peroxidase-like activity and TMB(colorless)was rapidly oxidized to oxTMB(blue)with the presence of H_(2)O_(2).Interestingly,the addition of low concentration of norfloxacin can accelerate the color reaction process of TMB,and blue deepening of the solution can be observed with the naked eye.However,after adding high concentration of norfloxacin,the activity of nanozymewas inhibited,resulting in the gradual fading of the solution.Based on this principle,a colorimetric sensor integrated with smartphone RGB mode was established.The visual sensor exhibited good linearity for norfloxacin monitoring in the range of 0.13-2.51μmol/L and 17.5-100μmol/L.The limit of visual detectionwas 0.08μmol/L.In the actualwater sample analysis,the spiked recoveries of norfloxacin were over the range of 95.7%-104.7%.These results demonstrated that the visual sensor was a convenient and fast method for the efficient and accurate detection of norfloxacin in water,which may have broad application prospect.展开更多
The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to...The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C.展开更多
Nanosphere-like Li2FeSiO4/C was synthesized via a solution method using sucrose as carbon sources under a mild condition of time-saving and energy-saving, followed by sintering at high temperatures for crystallization...Nanosphere-like Li2FeSiO4/C was synthesized via a solution method using sucrose as carbon sources under a mild condition of time-saving and energy-saving, followed by sintering at high temperatures for crystallization. The amount of carbon in the composite is less than 10% （mass fraction）, and the X-ray diffraction result confirms that the sample is of pure single phase indexed with the orthorhombic Pmn21 space group. The particle size of the Li2FeSiO4/C synthesized at 700 °C for 9 h is very fine and spherical-like with a size of 200 nm. The electrochemical performance of this material, including reversible capacity, cycle number, and charge-discharge characteristics, were tested. The cell of this sample can deliver a discharge capacity of 166 mA-h/g at C/20 rate in the first three cycles. After 30 cycles, the capacity decreases to 158 mA-h/g, and the capacity retention is up to 95%. The results show that this method can prepare nanosphere-like Li2FeSiO4/C composite with good electrochemical performance.展开更多
[Objective] This study aimed to establish a new method for determination of anemoside B4 content in pulsatilla water extract. [Method] Using acetonitrile-water （28：72） as the mobile phase, the high performance liqu...[Objective] This study aimed to establish a new method for determination of anemoside B4 content in pulsatilla water extract. [Method] Using acetonitrile-water （28：72） as the mobile phase, the high performance liquid chromatography, equipped with UV detector, was used to determine the anemoside B4 content in pulsatilla water extract. [Result] In the concentration range of 300-800 μg/ml, anemoside B4 content showed a good linear relationship with peak area. The average recovery of anemoside B4 was 98.12% （n=-6; RSD=-1.37%）. [Conclusion] The established method meets the requirements by methodology, and it can be used to determine the anemoside B4 content in pulsatilla water extract.展开更多
The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions f...The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.展开更多
在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、...在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)等手段对Zn-CdS/g-C_(3)N_(4)复合材料的形貌、结构和组成等进行了表征。结果表明,Zn-CdS纳米颗粒附着在g-C_(3)N_(4)表面上,从而形成Zn-CdS/g-C_(3)N_(4)复合材料,且复合后材料带隙减小,光生电子-空穴复合率降低。在500 W Xe灯照射下,研究了Zn-CdS/g-C_(3)N_(4)对罗丹明B(RhB)的光催化降解性能。在最优条件下,光照40 min后,所制备的Zn-CdS/g-C_(3)N_(4)对RhB的光催化降解效率达99%。此外,所合成的Zn-CdS/g-C_(3)N_(4)复合材料光稳定性较高、可再生性好。这归因于Zn和Cd的协同作用以及与g-C_(3)N_(4)的复合,促进了光生载流子的分离和转移。展开更多
To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vi...To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vis DRS techniques.The results showed that single or double doping did not change the crystalline structure and morphology,but the particle size decreased with Ni doping.The band gap energy absorption edge of Ni-B-BiVO4shifted to a longer wavelength compared with undoped,B or Ni single doped BiVO4.More V4+and surface hydroxyl oxygen were observed in BiVO4after Ni-B co-doping.When the optimal mass fraction of Ni is0.30%,the degradation rate of MO in50min is95%for0.3Ni-B-BiVO4sample which also can effectively degrade methyl blue(MB),acid orange(AOII)II and rhodamine B(RhB).The enhanced photocatalytic activity is attributed to the synergistic effects of B and Ni doping.展开更多
Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase ...Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcina- tion temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B（RhB） solution and gaseous formaldehyde（FAD）. With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550℃ for I0 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gase-ous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic per- formance of the prepared ZnWO4.展开更多
Long-lasting phosphor Y2O2S ： Eu^3＋ , Mg^2＋ , Ti^4＋ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased w...Long-lasting phosphor Y2O2S ： Eu^3＋ , Mg^2＋ , Ti^4＋ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S： Eu^3＋ （0.01 ≤ x ≤0.10）. On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S： Eu^3 ＋ crystal structure, Eu^3＋ ions only replaced Y^3 ＋ ions＇ places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm （5D1→^ 7F2 transition） to 626 nm （^5Do→^7TF2 transition）, and the maximum intensity was obtained when x = 0.09 in Y2O2S： Eu^3＋ （0.01 ≤x ≤0.10）. This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2＋ or Ti^4＋. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 ＋ and Ti^4 ＋ ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence （LLP） was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye （0.32 mcd·m^-2）. Thus the LLP mechanism was analyzed.展开更多
The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 6...The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 613 nm under the excitation of near-UV 394 nm. It was discussed in detail that the influence of the synthesis conditions such as the doping concentration of Bi3, the dose of citric acid, pH of the precursor solution and the sintering temperature on the emission intensity of the phosphors. According to the results, the optimal condition was obtained： the doping concentration of Bi3＋ was 15 mol.%, molar ratio of citric acid to metal ions was 1.5：1, pH of the precursor solution was 1.0 and the sintering temperature was 800 ℃. The X-ray diffraction （XRD） patterns of the LiEuo.85Bi0.15（MoO4）2 phosphor prepared under the optimal condition indicated that the phosphor was single phase with tetragonal scheelite structure. The Commission Intemationale de I＇E- clairage （CIE） chromaticity coordinates of LiEuo.85Bio.15（MoO4）2 were （x=0.655, y=0.345）, which were closer to the national television stan- dard committee （NTSC） standard values （x=0.670, y=0.330） than that of a commercial red phosphor of Y202S：Eu3＋（x=0.630, y=0.350）. This LiEuo.85Bi0As（MoO4）2 red phosphor is a promising candidate for the fabrication of white light-emitting diode （W-LED） with near-UV chips.展开更多
The aim of the study was to prepare berberine hydrochloride long-circulating liposomes and optimize the formulation and process parameters,and investigate the influence of different factors on the encapsulation effici...The aim of the study was to prepare berberine hydrochloride long-circulating liposomes and optimize the formulation and process parameters,and investigate the influence of different factors on the encapsulation efficiency.Berberine hydrochloride liposomes were prepared in response to a transmembrane ion gradient that was established by ionophore A23187.Free and liposomal drug were separated by cation exchange resin,and then the amount of intraliposomal berberine hydrochloride was determined by UV spectrophotometry.The optimized encapsulation efficiency of berberine hydrochloride liposomes was 94.3%2.1%when the drug-to-lipid ratio was 1:20,and the mean diameter was 146.9 nm3.2 nm.As a result,the ionophore A23187-mediated ZnSO_(4)gradient method was suitable for the preparation of berberine hydrochloride liposomes that we could get the desired encapsulation efficiency and drug loading.展开更多
Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the imp...Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho^3＋ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The result shows that Ho^3＋ ,Tm^3＋ , and Yb^3＋ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.展开更多
The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reducti...The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.展开更多
In this study,a novel solgel method has been developed to prepare LiTi_(2)(PO_(4))_(3) lithium ion conductor as monophase at relatively low temperature(600).According to the XRD and IR analysis,the asprepared sample r...In this study,a novel solgel method has been developed to prepare LiTi_(2)(PO_(4))_(3) lithium ion conductor as monophase at relatively low temperature(600).According to the XRD and IR analysis,the asprepared sample remained an amorphous state up to 500.The activation energy was calculated to be 252 kJ/mol according to the modified Kissinger equation.展开更多
In this study, the LiFePO_(4) cathode was synthesized by the ionic thermal method using the deep eutectic mixture of tetramethyl ammonium chloride and urea. The synthetic conditions were systematically investigated by...In this study, the LiFePO_(4) cathode was synthesized by the ionic thermal method using the deep eutectic mixture of tetramethyl ammonium chloride and urea. The synthetic conditions were systematically investigated by orthogonal experiments, which indicate that the optimal reaction time, reaction temperature, molar ratio of Li to DES and rotate speed are 96 h, 220 ℃, 1:14 and20 r·min^(-1), respectively. X-ray diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM) were characterized to investigate the crystalline structure and morphology of the obtained materials, indicating well-crystallized LiFePO_(4) with olivine structure. And the physical properties of LiFePO_(4) were explored through Fourier transform infrared spectroscopy(FTIR),57 Fe Mo¨ ssbauer absorption spectra and Raman spectra. An initial discharge capacity can reach 151 m Ah·g^(-1) at 0.1 C rate for LiFePO_(4) following by calcining at 600 ℃ under the optimal conditions, and it retains 125.1 m Ah·g^(-1) after 100 cycles. These results demonstrated that the addition of ionic liquids can improve the rate performance, cycle performance and ion diffusion rate of LiFePO_(4).展开更多
The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are syn...The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are synthesized via a self-template method and utilized as an efficient sulfur host material.The one-dimensional PCNNTs have a high specific surface area(143.47 m^(2)·g^(-1))and an abundance of macro-/mesopores,which could achieve a high sulfur loading rate of 74.7wt%.A Li-S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g^(-1).PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling.High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs.These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.展开更多
基金supported by the National Natural Science Foundation of China (No.21976211).
文摘Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria.However,the residual norfloxacin in the environment can be biomagnified via food chain andmay damage the human liver and delay the bone development ofminors.Present work described a reliable and sensitive smartphone colorimetric sensing system based on cobaltdoped Fe_(3)O_(4) magnetic nanoparticles(Co-Fe_(3)O_(4) MNPs)for the visual detection of norfloxacin.Compared with Fe_(3)O_(4),Co-Fe_(3)O_(4) MNPs earned more remarkably peroxidase-like activity and TMB(colorless)was rapidly oxidized to oxTMB(blue)with the presence of H_(2)O_(2).Interestingly,the addition of low concentration of norfloxacin can accelerate the color reaction process of TMB,and blue deepening of the solution can be observed with the naked eye.However,after adding high concentration of norfloxacin,the activity of nanozymewas inhibited,resulting in the gradual fading of the solution.Based on this principle,a colorimetric sensor integrated with smartphone RGB mode was established.The visual sensor exhibited good linearity for norfloxacin monitoring in the range of 0.13-2.51μmol/L and 17.5-100μmol/L.The limit of visual detectionwas 0.08μmol/L.In the actualwater sample analysis,the spiked recoveries of norfloxacin were over the range of 95.7%-104.7%.These results demonstrated that the visual sensor was a convenient and fast method for the efficient and accurate detection of norfloxacin in water,which may have broad application prospect.
基金Project (0991025) supported by Natural Science Foundation of Guangxi, ChinaProject (51164007) supported by the National Natural Science Foundation of ChinaProject (201101ZD008) supported by Educational Commission of Guangxi, China
文摘The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C.
基金Project supported by Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, China Project (2010JK765) supported by the Education Department of Shaanxi Province, China
文摘Nanosphere-like Li2FeSiO4/C was synthesized via a solution method using sucrose as carbon sources under a mild condition of time-saving and energy-saving, followed by sintering at high temperatures for crystallization. The amount of carbon in the composite is less than 10% （mass fraction）, and the X-ray diffraction result confirms that the sample is of pure single phase indexed with the orthorhombic Pmn21 space group. The particle size of the Li2FeSiO4/C synthesized at 700 °C for 9 h is very fine and spherical-like with a size of 200 nm. The electrochemical performance of this material, including reversible capacity, cycle number, and charge-discharge characteristics, were tested. The cell of this sample can deliver a discharge capacity of 166 mA-h/g at C/20 rate in the first three cycles. After 30 cycles, the capacity decreases to 158 mA-h/g, and the capacity retention is up to 95%. The results show that this method can prepare nanosphere-like Li2FeSiO4/C composite with good electrochemical performance.
基金Supported by General Program of Beijing Municipal Education Commission(KM201410020007)~~
文摘[Objective] This study aimed to establish a new method for determination of anemoside B4 content in pulsatilla water extract. [Method] Using acetonitrile-water （28：72） as the mobile phase, the high performance liquid chromatography, equipped with UV detector, was used to determine the anemoside B4 content in pulsatilla water extract. [Result] In the concentration range of 300-800 μg/ml, anemoside B4 content showed a good linear relationship with peak area. The average recovery of anemoside B4 was 98.12% （n=-6; RSD=-1.37%）. [Conclusion] The established method meets the requirements by methodology, and it can be used to determine the anemoside B4 content in pulsatilla water extract.
文摘The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.
文摘在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)等手段对Zn-CdS/g-C_(3)N_(4)复合材料的形貌、结构和组成等进行了表征。结果表明,Zn-CdS纳米颗粒附着在g-C_(3)N_(4)表面上,从而形成Zn-CdS/g-C_(3)N_(4)复合材料,且复合后材料带隙减小,光生电子-空穴复合率降低。在500 W Xe灯照射下,研究了Zn-CdS/g-C_(3)N_(4)对罗丹明B(RhB)的光催化降解性能。在最优条件下,光照40 min后,所制备的Zn-CdS/g-C_(3)N_(4)对RhB的光催化降解效率达99%。此外,所合成的Zn-CdS/g-C_(3)N_(4)复合材料光稳定性较高、可再生性好。这归因于Zn和Cd的协同作用以及与g-C_(3)N_(4)的复合,促进了光生载流子的分离和转移。
基金Projects (21207093,51004072) supported by the National Natural Science Foundation of China for YouthProject (LJQ2014023) supported by the Liaoning Excellent Talents in University,China+1 种基金Project (L20150178) supported by the General Scientific Research Projects Foundation of Liaoning Educational Committee,ChinaProject (N140303002) supported by the Fundamental Research Funds for the Central Universities,China
文摘To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vis DRS techniques.The results showed that single or double doping did not change the crystalline structure and morphology,but the particle size decreased with Ni doping.The band gap energy absorption edge of Ni-B-BiVO4shifted to a longer wavelength compared with undoped,B or Ni single doped BiVO4.More V4+and surface hydroxyl oxygen were observed in BiVO4after Ni-B co-doping.When the optimal mass fraction of Ni is0.30%,the degradation rate of MO in50min is95%for0.3Ni-B-BiVO4sample which also can effectively degrade methyl blue(MB),acid orange(AOII)II and rhodamine B(RhB).The enhanced photocatalytic activity is attributed to the synergistic effects of B and Ni doping.
基金Supported by the National Natural Science Foundation of China(Nos.20433010and20571047)Specialized Research Fundfor the Doctoral Program of Higher Education(No.20060003082).
文摘Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcina- tion temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B（RhB） solution and gaseous formaldehyde（FAD）. With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550℃ for I0 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gase-ous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic per- formance of the prepared ZnWO4.
文摘Long-lasting phosphor Y2O2S ： Eu^3＋ , Mg^2＋ , Ti^4＋ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S： Eu^3＋ （0.01 ≤ x ≤0.10）. On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S： Eu^3 ＋ crystal structure, Eu^3＋ ions only replaced Y^3 ＋ ions＇ places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm （5D1→^ 7F2 transition） to 626 nm （^5Do→^7TF2 transition）, and the maximum intensity was obtained when x = 0.09 in Y2O2S： Eu^3＋ （0.01 ≤x ≤0.10）. This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2＋ or Ti^4＋. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 ＋ and Ti^4 ＋ ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence （LLP） was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye （0.32 mcd·m^-2）. Thus the LLP mechanism was analyzed.
基金Project supported by National Natural Science Foundation of China (NSFC20803097, NSFC20603049)Natural Science Foundation of Chongqing (CSTC2011AB4056, CSTC2009BA4023)the Fundamental Research Funds for the Central Universities (CDJZR10220005 and CDJRC10220002)
文摘The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 613 nm under the excitation of near-UV 394 nm. It was discussed in detail that the influence of the synthesis conditions such as the doping concentration of Bi3, the dose of citric acid, pH of the precursor solution and the sintering temperature on the emission intensity of the phosphors. According to the results, the optimal condition was obtained： the doping concentration of Bi3＋ was 15 mol.%, molar ratio of citric acid to metal ions was 1.5：1, pH of the precursor solution was 1.0 and the sintering temperature was 800 ℃. The X-ray diffraction （XRD） patterns of the LiEuo.85Bi0.15（MoO4）2 phosphor prepared under the optimal condition indicated that the phosphor was single phase with tetragonal scheelite structure. The Commission Intemationale de I＇E- clairage （CIE） chromaticity coordinates of LiEuo.85Bio.15（MoO4）2 were （x=0.655, y=0.345）, which were closer to the national television stan- dard committee （NTSC） standard values （x=0.670, y=0.330） than that of a commercial red phosphor of Y202S：Eu3＋（x=0.630, y=0.350）. This LiEuo.85Bi0As（MoO4）2 red phosphor is a promising candidate for the fabrication of white light-emitting diode （W-LED） with near-UV chips.
文摘The aim of the study was to prepare berberine hydrochloride long-circulating liposomes and optimize the formulation and process parameters,and investigate the influence of different factors on the encapsulation efficiency.Berberine hydrochloride liposomes were prepared in response to a transmembrane ion gradient that was established by ionophore A23187.Free and liposomal drug were separated by cation exchange resin,and then the amount of intraliposomal berberine hydrochloride was determined by UV spectrophotometry.The optimized encapsulation efficiency of berberine hydrochloride liposomes was 94.3%2.1%when the drug-to-lipid ratio was 1:20,and the mean diameter was 146.9 nm3.2 nm.As a result,the ionophore A23187-mediated ZnSO_(4)gradient method was suitable for the preparation of berberine hydrochloride liposomes that we could get the desired encapsulation efficiency and drug loading.
基金Project supported bythe Key Laboratory of Rare Earth Chemistry and Physics ,ChangchunInstitute of Applied Chemistry ,Chinese Academy of Sciences (R020202K)
文摘Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho^3＋ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The result shows that Ho^3＋ ,Tm^3＋ , and Yb^3＋ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.
基金Project supported by the National Natural Science Foundation of China(21876168)the Key Projects for Common Key Technology Innovation in Key Industries in Chongqing(cstc2016zdcy-ztzx0020-01)+1 种基金Youth Innovation Promotion Association CAS(2019376)the Graduate Innovation Project of Chongqing Technology and Business University(yjscxx201803-028-22)。
文摘The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.
文摘In this study,a novel solgel method has been developed to prepare LiTi_(2)(PO_(4))_(3) lithium ion conductor as monophase at relatively low temperature(600).According to the XRD and IR analysis,the asprepared sample remained an amorphous state up to 500.The activation energy was calculated to be 252 kJ/mol according to the modified Kissinger equation.
基金financially supported by the National Natural Science Foundation of China (Nos. 51674068,51874079, 51804035 and 11775226)the Natural Science Foundation of Hebei Province (No. E2018501091)+2 种基金Hebei Province Key Research and Development Plan Project (No. 19211302D)the Fundamental Research Funds for the Central Universities (Nos. N172302001,N182306001, N182312007, N182304018 and N2023040)Research Project on Distribution of Heavy Metals in Soil and Comprehensive Utilization Technology of Tailings in Typical Iron Tailing Reservoir Areas of Hebei Province (No. 802060671901)。
文摘In this study, the LiFePO_(4) cathode was synthesized by the ionic thermal method using the deep eutectic mixture of tetramethyl ammonium chloride and urea. The synthetic conditions were systematically investigated by orthogonal experiments, which indicate that the optimal reaction time, reaction temperature, molar ratio of Li to DES and rotate speed are 96 h, 220 ℃, 1:14 and20 r·min^(-1), respectively. X-ray diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM) were characterized to investigate the crystalline structure and morphology of the obtained materials, indicating well-crystallized LiFePO_(4) with olivine structure. And the physical properties of LiFePO_(4) were explored through Fourier transform infrared spectroscopy(FTIR),57 Fe Mo¨ ssbauer absorption spectra and Raman spectra. An initial discharge capacity can reach 151 m Ah·g^(-1) at 0.1 C rate for LiFePO_(4) following by calcining at 600 ℃ under the optimal conditions, and it retains 125.1 m Ah·g^(-1) after 100 cycles. These results demonstrated that the addition of ionic liquids can improve the rate performance, cycle performance and ion diffusion rate of LiFePO_(4).
基金financially supported by the Natural Science Sci-ence Foundation of Jiangsu Province,China(No.BK20181469)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110035)the Science and Technology Planning Social Development Project of Zhenji-ang City,China(No.SSH20190140049).
文摘The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are synthesized via a self-template method and utilized as an efficient sulfur host material.The one-dimensional PCNNTs have a high specific surface area(143.47 m^(2)·g^(-1))and an abundance of macro-/mesopores,which could achieve a high sulfur loading rate of 74.7wt%.A Li-S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g^(-1).PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling.High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs.These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.
