In this study we used a chemical solution method from oxalic acid (OX. acid) and zinc acetate (ZnAc) to prepare Zinc Oxide nanoparticles (ZnONPs) and Zinc Oxide nanoparticles doped with Chlorine (Cl:ZnONPs). The chara...In this study we used a chemical solution method from oxalic acid (OX. acid) and zinc acetate (ZnAc) to prepare Zinc Oxide nanoparticles (ZnONPs) and Zinc Oxide nanoparticles doped with Chlorine (Cl:ZnONPs). The characterizations (FTIR, X-ray, SEM, TEM) of ZnONPs and Cl:ZnONPs were determined. Amylase inhibitors of ZnONPs and Cl:ZnONPs also were determined. SEM indicated that the ZnONPs and Cl:ZnONPs have an average particle size of 46.65 - 74.64 nm. TEM images of the ZnONPs and Cl:ZnONPs showed the round shaped. Compounds b,<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">d and e exhibited significant inhibitory activity against amylase enzyme</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">(from 69.21</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">±</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">1.44 to 76.32</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">±</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">0.78), respectively, and were comparable with that of acarbose (86.32 ± 0.63) at 1000</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">μg, thereby, projecting ZnONPs and Cl:ZnONPs as </span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;">-amylase inhibitors.</span></span></span></span>展开更多
High transparent and conductive thin films of zinc doped tin oxide (ZTO) were deposited on quartz substrates by the radio-frequency (RF) magnetron sputtering using a 12 wt% ZnO doped with 88 wt% SnO2 ceramic targe...High transparent and conductive thin films of zinc doped tin oxide (ZTO) were deposited on quartz substrates by the radio-frequency (RF) magnetron sputtering using a 12 wt% ZnO doped with 88 wt% SnO2 ceramic target.The effect of substrate temperature on the structural,electrical and optical performances of ZTO films has been studied.X-ray diffraction (XRD) results show that ZTO films possess tetragonal rutile structure with the preferred orientation of (101).The surface morphology and roughness of the films was investigated by the atomic force microscope (AFM).The electrical characteristic (including carrier concentration,Hall mobility and resistivity) and optical transmittance were studied by the Hall tester and UV- VIS,respectively.The highest carrier concentration of -1.144×1020 cm-3 and the Hall mobility of 7.018 cm2(V ·sec)-1 for the film with an average transmittance of about 80.0% in the visible region and the lowest resistivity of 1.116×10-2 Ω·cm were obtained when the ZTO films deposited at 250 oC.展开更多
Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by contro...Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by controlling precursor sol composition.Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration.Uniform and highly transparent FTO films,with more than 85%of optical transmittance,were obtained by annealing at 600℃.Florine doping of films was verified by analyzing the valence band region obtained by XPS.It was found that the fluorine doping affects the shape of valence band of SnO2 films.In addition,it was observed that the band gap of SnO2 is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.展开更多
Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of ace...Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10^-3 Ω. cm and particle grains. The doublelayers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.58 × 10^-3 Ω. cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substratelayer, and the second-layer plays a large part in the resistivity of the doublewlayer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated.展开更多
Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal cata...Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.展开更多
Zinc oxide(ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction(XRD), scanning electron microscopic(SEM), UVabsorption spectroscopy, ...Zinc oxide(ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction(XRD), scanning electron microscopic(SEM), UVabsorption spectroscopy, photoluminescence(PL) study and vibrating sample magnetometer. The XRD studies exhibit the presence of wurtzite crystal structure similar to the parent compound ZnO in 1% Er^(3+)doped Zn O,suggesting that doped Er^(3+)ions sit at the regular Zn^(2+)sites. However, same studies spread over the samples with Er^(3+)content>1% reveals the occurrence of secondary phase. SEM images of 1% Er^(3+)doped ZnO show the polycrystalline nature of the synthesized sample. UV-visible absorption spectrum of Er^(3+)doped ZnO nanocrystals shows a strong absorption peak at 388 nm due to ZnO band to band transition. The PL study exhibits emission in the visible region, due to excitonic as well as defect related transitions. The magnetizationfield curve of Er^(3+)doped ZnO nanocrystals showed ferromagnetic property at room-temperature.展开更多
Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. F...Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. Furthermore, the influences of dysprosium oxide doping fraction on grain size and dielectric properties of barium titanate ceramic, including dielectric constant and breakdown electric field strength , were investigated via scanning electron microscope, X-ray diffraction and electric property tester. The results show that dysprosium oxide can restrain abnormal grain growth during sintering and that fine-grained and high density of barium titanate ceramic can result in excellent dielectric properties. As mass fraction of dysprosium oxide is 0.6%, the lattice parameters of grain increase to the maximum because of the lowest vacancy concentration. The electric property parameters are cited as following: dielectric constant (25 ℃ ) reaches 4100, the change in relative dielectric constant with temperature is - 10% to 10% within the range of - 15 - 100 ℃, breakdown electric field strength (alternating current) achieves 3.2 kV·mm^-1, which can be used in manufacturing high voltage ceramic capacitors展开更多
Samples doped with different amount of dysprosium oxide into barium strontium titanate (BSTO) were prepared. Dielectric properties of the samples at high frequency were discussed. X-ray diffraction (XRD) method was em...Samples doped with different amount of dysprosium oxide into barium strontium titanate (BSTO) were prepared. Dielectric properties of the samples at high frequency were discussed. X-ray diffraction (XRD) method was employed for analyzing and comparing with the changes in the crystal lattice of the samples,and information of crystal growth was obtained through method of environmental scanning electron micrograph (ESEM). Influence of dysprosium oxide doping on dielectric properties of BSTO based ceramic system at high frequency was studied. Phenomenological coefficients of the samples were calculated on the base of tunability.展开更多
Via the first principles calculations, we predict that Cu doped graphene oxide (GO) is a much better nanocatalyst in terms of activity and feasibility. The high activity of Cu doped graphene oxides may be attributed...Via the first principles calculations, we predict that Cu doped graphene oxide (GO) is a much better nanocatalyst in terms of activity and feasibility. The high activity of Cu doped graphene oxides may be attributed to the charge transfer between the GO and Cu atom, resulting in an activated Cu atom. In the ER mechanism, the CO molecules directly react with the activated O2, then forming a metastable carbonate-like intermediate state (OOCO). The reaction may proceed via two reaction paths of OOCO → CO2 + O and CO + OOCO → 2CO2, respectively. The calculated results show that the latter path is relatively more thermodynamically favorable with a modest energy barrier, so it should be more preferred. We expect our theoretical predictions to open a new avenue to fabricate carbon-based catalysts for CO oxidation with lower cost and higher activity.展开更多
α-Fe2O3 nanoparticles doped with various molar fractions of Cr^3+ were synthesized by a forced hydrolysis route and were characterized by X-ray diffraction(XRD),scanning electronic microscopy(SEM),X-ray photoele...α-Fe2O3 nanoparticles doped with various molar fractions of Cr^3+ were synthesized by a forced hydrolysis route and were characterized by X-ray diffraction(XRD),scanning electronic microscopy(SEM),X-ray photoelectron spectroscopy(XPS) and inductive coupled plasma(ICP) techniques.The particles reserve shuttle-like shape in the presence of Cr^3+.The crystallite sizes of Fe2O3 become smaller with the increased Cr^3+ concentration in solution.The responses of Cr doped α-Fe2O3 sensors were studied towards reducing gases such as ethanol,methanol,acetone,gasoline and n-hexane.Gas sensors based on these materials have higher sensitivities and rapid response/recovery time to alcohol than to hydrocarbon.展开更多
Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2...Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2,3,and 5 wt%).Cu-doped ZnO thin films were prepared on p-Si(100)substrate by screen printing method.Cu-doped ZnO/Si films were annealed at different temperatures from 300 to 700°C.In this study,Cu-doped ZnO structures were prepared by a simple precipitation technique,and characterized by various techniques such as XRD(X-ray diffraction)and SEM(scanning electron microscope).The electrical properties of Cu-doped ZnO/Si were measured.It has found that Cu-doped ZnO/Si films can be used as optoelectronic devices.展开更多
Brownmillerite-type oxides Ba_2In_(2-x-y)Mn_xAl_yO_(5+x)(0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5) were prepared at 1300°C through solid-state reaction. X-ray diffraction(XRD) analysis showed that the structure symm...Brownmillerite-type oxides Ba_2In_(2-x-y)Mn_xAl_yO_(5+x)(0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5) were prepared at 1300°C through solid-state reaction. X-ray diffraction(XRD) analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl_2O_4 and Ba_2InAlO_5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn(x ≤ 0.3), the Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) was confirmed to be +5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) samples is rooted in the existence of Mn^(5+); thus, the introduction of Al does not affect the optical properties of the compounds.展开更多
Na_2CO_3/ZrO_2 catalyst shows a high activity of oxidative coupling of methane. It possesses stronger electron donor ability than that of ZrO_2 catalyst. The activation of methane is supposed to relate to the O_2^- or...Na_2CO_3/ZrO_2 catalyst shows a high activity of oxidative coupling of methane. It possesses stronger electron donor ability than that of ZrO_2 catalyst. The activation of methane is supposed to relate to the O_2^- or O_2^(2-) and O^- species.展开更多
Through measuring the alkali resistance of the invert glass and the quantity of SiO 2 and TiO 2 migrating fron the glass into the solution,the influence of TiO 2 on the alkali resistance of the glass is discussed a...Through measuring the alkali resistance of the invert glass and the quantity of SiO 2 and TiO 2 migrating fron the glass into the solution,the influence of TiO 2 on the alkali resistance of the glass is discussed and its structure is also analyzed by infrared spectroscopy.It is concluded that TiO 2 has double functions for the alkali resistance of the invert glass.On the one hand ,both TiO 2 polarizing the secondary ions in glass and TiO 2 isomorphism replacement of SiO 2 make the alkali resistance of the glass decrease.On the ther hand,TiO 2 patching network and anti erosion covering help to increase the alkali resistance.展开更多
Conducting nanocomposites of poly (methyl methacrylate) (PMMA) and antimony doped tin oxide (ATO) were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stabili...Conducting nanocomposites of poly (methyl methacrylate) (PMMA) and antimony doped tin oxide (ATO) were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stability, and mechanical properties of the nanocomposites were investigated. A homogeneous dispersion of silane coupling agent modified ATO was achieved in PMMA matrix as evidenced by scanning electron microscopy. The resultant PMMA/silane-ATO nanocomposites were electrically conductive with significant conductivity enhancement at 4 wt pct. It was found that the composition at 4 wt pct ATO gave the higher tensile strength. Furthermore, it gave the largest elongation at break value among all the compositions. Thermal stability of the nanocomposites was remarkably enhanced by the incorporation of silane-ATO.展开更多
Cu-Ce-O catalysts, prepared by the amorphous citrate precursor (ACP) method, wereinvestigated by ICP, XRD and ndcro-reactor techniques. At low copper content of Cu-Ce-Ocatalysts, fluorite structures formed at low calc...Cu-Ce-O catalysts, prepared by the amorphous citrate precursor (ACP) method, wereinvestigated by ICP, XRD and ndcro-reactor techniques. At low copper content of Cu-Ce-Ocatalysts, fluorite structures formed at low calcining temperatures, and Cuo doped into the CeO2matrix; at high copper content, in addition to the fluorite structure, crystalline monoclinic phaseCuO formed as well at high calcining temperatures. There was no other phase formed even calcinedat 1000℃. The results show that only a little CuO dopes into the CeO2 matrix to form complexoxide, which promotes the catalytic activity of CO oxidation greatly. The optimum Cu-Ce-Ocatalyst is composed of 15% copper by Cu/(Ce+Cu) atomic ratio, and calcined at 700℃ for 4h. Thephase compositions include the crystalline CuO and the active complex oxide with fluoritestructure. The formulation of the active complex oxide is Cu0.06Ce0. 94O1.94.展开更多
The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders(in the range of 0.25-15 mol%) were reported in this paper.I-phase samples,which were indexed as single phase with a hexa...The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders(in the range of 0.25-15 mol%) were reported in this paper.I-phase samples,which were indexed as single phase with a hexagonal(wurtzite) structure in the Fe-doped ZnO binary system,were determined by X-ray diffraction(XRD).The solubility limit of Fe in the ZnO lattice is 3 mol% at 950℃.The above mixed phase was observed.And the impurity phase was determined as the cubic-ZnFe 2 O 4 phase when compared with standard XRD data using the PDF program.This study focused on single I-phase ZnO samples which were synthesized at 950℃ because the limit of the solubility range is the widest at this temperature.The lattice parameters a and c of the I-phase decreased with Fe-doping concentration.The morphology of the I-phase samples was analyzed with a scanning electron microscope.The grain size of the I-phase samples increased with heat treatment and doping concentration.The electrical conductivity of the pure ZnO and single I-phase samples was investigated using the four-probe dc method at 100-950℃ in air atmosphere.The electrical conductivity values of pure ZnO,0.25 and 3 mol% Fe-doped ZnO samples at 100℃ were 2×10-6,1.7×10-3 and 6.3×10-4 S.cm-1,and at 950℃ they were 3.4,8.5 and 4 S.cm-1,respectively.展开更多
Antimony doped tin oxide(ATO) thin films have been prepared by pulsed laser deposition(PLD) method.The intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb(3+) and Sb(5+) and c...Antimony doped tin oxide(ATO) thin films have been prepared by pulsed laser deposition(PLD) method.The intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb(3+) and Sb(5+) and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated.It is suggested that the transition degree of Sb(3+) towards Sb(5+)(Sb(5+)/Sb(3+) ratio) is determined by Sb content.When the Sb content is increased to 12 at%,the Sb(5+)/Sb(3+) ratio reaches the highest value of 2.05,corresponding to the resistivity of 2.70×10(-3) Ω·cm.Meanwhile,the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%,corresponding to the highest average optical transmittance of 92%.Comprehensively considering the combination of electrical and optical properties,the ATO thin films deposited with Sb content of 12 at%exhibit the best properties with the highest "figure of merit" of 3.85×10(-3) Ω(-1).Finally,an antimony selenide(Sb_2Se_3) heterojunction solar cell prototype with the ATO thin film as the anode has been prepared,and a power conversion efficiency of 0.83%has been achieved.展开更多
Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control ...Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.展开更多
文摘In this study we used a chemical solution method from oxalic acid (OX. acid) and zinc acetate (ZnAc) to prepare Zinc Oxide nanoparticles (ZnONPs) and Zinc Oxide nanoparticles doped with Chlorine (Cl:ZnONPs). The characterizations (FTIR, X-ray, SEM, TEM) of ZnONPs and Cl:ZnONPs were determined. Amylase inhibitors of ZnONPs and Cl:ZnONPs also were determined. SEM indicated that the ZnONPs and Cl:ZnONPs have an average particle size of 46.65 - 74.64 nm. TEM images of the ZnONPs and Cl:ZnONPs showed the round shaped. Compounds b,<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">d and e exhibited significant inhibitory activity against amylase enzyme</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">(from 69.21</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">±</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">1.44 to 76.32</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">±</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">0.78), respectively, and were comparable with that of acarbose (86.32 ± 0.63) at 1000</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">μg, thereby, projecting ZnONPs and Cl:ZnONPs as </span><i><span style="font-family:Verdana;">α</span></i><span style="font-family:Verdana;">-amylase inhibitors.</span></span></span></span>
基金Funded by the Program for Changjiang Scholars and Innovative Research Team in University, Ministry of Education, China (No.IRT0547)
文摘High transparent and conductive thin films of zinc doped tin oxide (ZTO) were deposited on quartz substrates by the radio-frequency (RF) magnetron sputtering using a 12 wt% ZnO doped with 88 wt% SnO2 ceramic target.The effect of substrate temperature on the structural,electrical and optical performances of ZTO films has been studied.X-ray diffraction (XRD) results show that ZTO films possess tetragonal rutile structure with the preferred orientation of (101).The surface morphology and roughness of the films was investigated by the atomic force microscope (AFM).The electrical characteristic (including carrier concentration,Hall mobility and resistivity) and optical transmittance were studied by the Hall tester and UV- VIS,respectively.The highest carrier concentration of -1.144×1020 cm-3 and the Hall mobility of 7.018 cm2(V ·sec)-1 for the film with an average transmittance of about 80.0% in the visible region and the lowest resistivity of 1.116×10-2 Ω·cm were obtained when the ZTO films deposited at 250 oC.
文摘Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by controlling precursor sol composition.Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration.Uniform and highly transparent FTO films,with more than 85%of optical transmittance,were obtained by annealing at 600℃.Florine doping of films was verified by analyzing the valence band region obtained by XPS.It was found that the fluorine doping affects the shape of valence band of SnO2 films.In addition,it was observed that the band gap of SnO2 is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.
基金supported by Hi-Tech Research and Development Program of China (Grant Nos. 2007AA05Z436 and 2009AA050602)Science and Technology Support Project of Tianjin (Grant No. 08ZCKFGX03500)+3 种基金the National Basic Research Program of China (Grant Nos. 2011CB201605 and 2011CB201606)the National Natural Science Foundation of China (Grant No. 60976051)International Cooperation Project between China-Greece Government (Grant No. 2009DFA62580)Program for New Century Excellent Talents in University of China (Grant No. NCET-08-0295)
文摘Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10^-3 Ω. cm and particle grains. The doublelayers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.58 × 10^-3 Ω. cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substratelayer, and the second-layer plays a large part in the resistivity of the doublewlayer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated.
基金supported by the National Innovation Agency of Portugal through the project Baterias 2030(Grant No.POCI-01-0247-FEDER-046109)J R E would like to acknowledge the Fundación General CSIC’s ComFuturo programme which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.101034263+2 种基金The authors appreciate Dr Laura Simonelli and Dr Vlad Martin Diaconescu for their assistance in XAS measurements at the beamline BL22-CLÆSS,ALBA synchrotron(experiment AV-2022025706)R M is grateful to the Portuguese Foundation for Science and Technology(FCT)for the doctoral grant(Grant No.2021.06496.BD)R M and A M are grateful for the financial support from:LA/P/0045/2020,UIDB/00511/2020 and UIDP/00511/2020,funded by the national funds through FCT/MCTES(PIDDAC)。
文摘Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.
文摘Zinc oxide(ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction(XRD), scanning electron microscopic(SEM), UVabsorption spectroscopy, photoluminescence(PL) study and vibrating sample magnetometer. The XRD studies exhibit the presence of wurtzite crystal structure similar to the parent compound ZnO in 1% Er^(3+)doped Zn O,suggesting that doped Er^(3+)ions sit at the regular Zn^(2+)sites. However, same studies spread over the samples with Er^(3+)content>1% reveals the occurrence of secondary phase. SEM images of 1% Er^(3+)doped ZnO show the polycrystalline nature of the synthesized sample. UV-visible absorption spectrum of Er^(3+)doped ZnO nanocrystals shows a strong absorption peak at 388 nm due to ZnO band to band transition. The PL study exhibits emission in the visible region, due to excitonic as well as defect related transitions. The magnetizationfield curve of Er^(3+)doped ZnO nanocrystals showed ferromagnetic property at room-temperature.
文摘Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. Furthermore, the influences of dysprosium oxide doping fraction on grain size and dielectric properties of barium titanate ceramic, including dielectric constant and breakdown electric field strength , were investigated via scanning electron microscope, X-ray diffraction and electric property tester. The results show that dysprosium oxide can restrain abnormal grain growth during sintering and that fine-grained and high density of barium titanate ceramic can result in excellent dielectric properties. As mass fraction of dysprosium oxide is 0.6%, the lattice parameters of grain increase to the maximum because of the lowest vacancy concentration. The electric property parameters are cited as following: dielectric constant (25 ℃ ) reaches 4100, the change in relative dielectric constant with temperature is - 10% to 10% within the range of - 15 - 100 ℃, breakdown electric field strength (alternating current) achieves 3.2 kV·mm^-1, which can be used in manufacturing high voltage ceramic capacitors
文摘Samples doped with different amount of dysprosium oxide into barium strontium titanate (BSTO) were prepared. Dielectric properties of the samples at high frequency were discussed. X-ray diffraction (XRD) method was employed for analyzing and comparing with the changes in the crystal lattice of the samples,and information of crystal growth was obtained through method of environmental scanning electron micrograph (ESEM). Influence of dysprosium oxide doping on dielectric properties of BSTO based ceramic system at high frequency was studied. Phenomenological coefficients of the samples were calculated on the base of tunability.
基金supported by the National Natural Science Foundation of China(No.21004009)the Foundation of Jiangxi Educational Committee(No.GJJ14485)
文摘Via the first principles calculations, we predict that Cu doped graphene oxide (GO) is a much better nanocatalyst in terms of activity and feasibility. The high activity of Cu doped graphene oxides may be attributed to the charge transfer between the GO and Cu atom, resulting in an activated Cu atom. In the ER mechanism, the CO molecules directly react with the activated O2, then forming a metastable carbonate-like intermediate state (OOCO). The reaction may proceed via two reaction paths of OOCO → CO2 + O and CO + OOCO → 2CO2, respectively. The calculated results show that the latter path is relatively more thermodynamically favorable with a modest energy barrier, so it should be more preferred. We expect our theoretical predictions to open a new avenue to fabricate carbon-based catalysts for CO oxidation with lower cost and higher activity.
基金Supported by the National Natural Science Foundation of China(No.40772026)
文摘α-Fe2O3 nanoparticles doped with various molar fractions of Cr^3+ were synthesized by a forced hydrolysis route and were characterized by X-ray diffraction(XRD),scanning electronic microscopy(SEM),X-ray photoelectron spectroscopy(XPS) and inductive coupled plasma(ICP) techniques.The particles reserve shuttle-like shape in the presence of Cr^3+.The crystallite sizes of Fe2O3 become smaller with the increased Cr^3+ concentration in solution.The responses of Cr doped α-Fe2O3 sensors were studied towards reducing gases such as ethanol,methanol,acetone,gasoline and n-hexane.Gas sensors based on these materials have higher sensitivities and rapid response/recovery time to alcohol than to hydrocarbon.
文摘Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2,3,and 5 wt%).Cu-doped ZnO thin films were prepared on p-Si(100)substrate by screen printing method.Cu-doped ZnO/Si films were annealed at different temperatures from 300 to 700°C.In this study,Cu-doped ZnO structures were prepared by a simple precipitation technique,and characterized by various techniques such as XRD(X-ray diffraction)and SEM(scanning electron microscope).The electrical properties of Cu-doped ZnO/Si were measured.It has found that Cu-doped ZnO/Si films can be used as optoelectronic devices.
基金financially supported by the National Natural Science Foundation of China (No.51402016)the Fundamental Research Funds for the Central Universities (No.FRF-TP-15-008A2)
文摘Brownmillerite-type oxides Ba_2In_(2-x-y)Mn_xAl_yO_(5+x)(0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5) were prepared at 1300°C through solid-state reaction. X-ray diffraction(XRD) analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl_2O_4 and Ba_2InAlO_5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn(x ≤ 0.3), the Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) was confirmed to be +5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) samples is rooted in the existence of Mn^(5+); thus, the introduction of Al does not affect the optical properties of the compounds.
基金Supported by the National Natural Science Foundation of China
文摘Na_2CO_3/ZrO_2 catalyst shows a high activity of oxidative coupling of methane. It possesses stronger electron donor ability than that of ZrO_2 catalyst. The activation of methane is supposed to relate to the O_2^- or O_2^(2-) and O^- species.
文摘Through measuring the alkali resistance of the invert glass and the quantity of SiO 2 and TiO 2 migrating fron the glass into the solution,the influence of TiO 2 on the alkali resistance of the glass is discussed and its structure is also analyzed by infrared spectroscopy.It is concluded that TiO 2 has double functions for the alkali resistance of the invert glass.On the one hand ,both TiO 2 polarizing the secondary ions in glass and TiO 2 isomorphism replacement of SiO 2 make the alkali resistance of the glass decrease.On the ther hand,TiO 2 patching network and anti erosion covering help to increase the alkali resistance.
文摘Conducting nanocomposites of poly (methyl methacrylate) (PMMA) and antimony doped tin oxide (ATO) were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stability, and mechanical properties of the nanocomposites were investigated. A homogeneous dispersion of silane coupling agent modified ATO was achieved in PMMA matrix as evidenced by scanning electron microscopy. The resultant PMMA/silane-ATO nanocomposites were electrically conductive with significant conductivity enhancement at 4 wt pct. It was found that the composition at 4 wt pct ATO gave the higher tensile strength. Furthermore, it gave the largest elongation at break value among all the compositions. Thermal stability of the nanocomposites was remarkably enhanced by the incorporation of silane-ATO.
文摘Cu-Ce-O catalysts, prepared by the amorphous citrate precursor (ACP) method, wereinvestigated by ICP, XRD and ndcro-reactor techniques. At low copper content of Cu-Ce-Ocatalysts, fluorite structures formed at low calcining temperatures, and Cuo doped into the CeO2matrix; at high copper content, in addition to the fluorite structure, crystalline monoclinic phaseCuO formed as well at high calcining temperatures. There was no other phase formed even calcinedat 1000℃. The results show that only a little CuO dopes into the CeO2 matrix to form complexoxide, which promotes the catalytic activity of CO oxidation greatly. The optimum Cu-Ce-Ocatalyst is composed of 15% copper by Cu/(Ce+Cu) atomic ratio, and calcined at 700℃ for 4h. Thephase compositions include the crystalline CuO and the active complex oxide with fluoritestructure. The formulation of the active complex oxide is Cu0.06Ce0. 94O1.94.
基金supported by the Research Foundation of Erciyes University (Kayseri,Turkey)
文摘The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders(in the range of 0.25-15 mol%) were reported in this paper.I-phase samples,which were indexed as single phase with a hexagonal(wurtzite) structure in the Fe-doped ZnO binary system,were determined by X-ray diffraction(XRD).The solubility limit of Fe in the ZnO lattice is 3 mol% at 950℃.The above mixed phase was observed.And the impurity phase was determined as the cubic-ZnFe 2 O 4 phase when compared with standard XRD data using the PDF program.This study focused on single I-phase ZnO samples which were synthesized at 950℃ because the limit of the solubility range is the widest at this temperature.The lattice parameters a and c of the I-phase decreased with Fe-doping concentration.The morphology of the I-phase samples was analyzed with a scanning electron microscope.The grain size of the I-phase samples increased with heat treatment and doping concentration.The electrical conductivity of the pure ZnO and single I-phase samples was investigated using the four-probe dc method at 100-950℃ in air atmosphere.The electrical conductivity values of pure ZnO,0.25 and 3 mol% Fe-doped ZnO samples at 100℃ were 2×10-6,1.7×10-3 and 6.3×10-4 S.cm-1,and at 950℃ they were 3.4,8.5 and 4 S.cm-1,respectively.
基金Funded by the International Science&Technology Cooperation Program of China(No.2011DFA52650)the"111"Project(No.B13035)+1 种基金the National Natural Science Foundation of China(No.51521001)the Fundamental Research Funds for the Central Universities
文摘Antimony doped tin oxide(ATO) thin films have been prepared by pulsed laser deposition(PLD) method.The intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb(3+) and Sb(5+) and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated.It is suggested that the transition degree of Sb(3+) towards Sb(5+)(Sb(5+)/Sb(3+) ratio) is determined by Sb content.When the Sb content is increased to 12 at%,the Sb(5+)/Sb(3+) ratio reaches the highest value of 2.05,corresponding to the resistivity of 2.70×10(-3) Ω·cm.Meanwhile,the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%,corresponding to the highest average optical transmittance of 92%.Comprehensively considering the combination of electrical and optical properties,the ATO thin films deposited with Sb content of 12 at%exhibit the best properties with the highest "figure of merit" of 3.85×10(-3) Ω(-1).Finally,an antimony selenide(Sb_2Se_3) heterojunction solar cell prototype with the ATO thin film as the anode has been prepared,and a power conversion efficiency of 0.83%has been achieved.
文摘Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.