Spherical YAG:Ce^3+ phosphor particles with narrow size distribution were prepared by spray pyrolysis. The effects of the concentration of solution, the flow rate of cartier gas and the annexing temperature on the p...Spherical YAG:Ce^3+ phosphor particles with narrow size distribution were prepared by spray pyrolysis. The effects of the concentration of solution, the flow rate of cartier gas and the annexing temperature on the phosphor morphology were studied. The productivity of precursor particles shows a trend of drop after rising with the increase of concentration Raising the flow rate of nitrogen can improve the productivity of the precursor particles. Phosphor prepared by spray pyrolysis has obviously higher emission intensity than that synthesized by solid state reaction, spray pyrolysis makes Ce^3+ ions well distributed in the crystal lattice as the luminescent centers, and phosphor particles have regular sphericity and narrow size distribution.展开更多
Boron-doped NiO thin films were prepared on glass substrates at 400℃ by airbrush spraying method using a solution of nickel nitrate hexahydrate. Their physical properties were investigated as a function of dopant con...Boron-doped NiO thin films were prepared on glass substrates at 400℃ by airbrush spraying method using a solution of nickel nitrate hexahydrate. Their physical properties were investigated as a function of dopant concentration. From X-ray diffraction patterns, it is observed that the films have cubic structure with lattice parameters varying with boron concentration. The morphologies of the films were examined by using scanning electron microscopy, and the grain sizes were measured to be around 30-50 nm. Optical measurements show that the band gap energies of the films first decrease then increase with increasing boron concentration. The resistivities of the films were determined by four point probe method, and the changes in resistivity with boron concentration were investigated.展开更多
ZnO nanoparticles and porous particles were produced by an ultrasonic spray pyrolysis method using a zinc nitrate precursor at various temperatures under air atmosphere. The effects of reaction temperature on the size...ZnO nanoparticles and porous particles were produced by an ultrasonic spray pyrolysis method using a zinc nitrate precursor at various temperatures under air atmosphere. The effects of reaction temperature on the size and morphology of ZnO particles were investi- gated. The samples were characterized by energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. ZnO particles were obtained in a hexagonal crystal structure and the crystallite shapes changed from spherical to hex- agonal by elevating the reaction temperature. The crystallite size grew by increasing the temperature, in spite of reducing the residence time in the heated zone. ZnO nanoparticles were obtained at the lowest reaction temperature and ZnO porous particles, formed by aggregation of ZnO nanoparticles due to effective sintering, were prepared at higher temperatures. The results showed that the properties of ZnO particles can be controlled by changing the reaction temperature in the ultrasonic spray pyrolysis method.展开更多
The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge....The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge.However,there is a lack of facile techniques for depositing compact catalytic films of high coverage and possessing a state-of-the-art performance,which is especially desired in photoelectrochemical(PEC)systems.Herein,we demonstrate a spray pyrolysis(SP)route to address this issue,featuring the kinetic selective preparation towards the desired catalytic-active material.Differing from reported SP protocols which only produce inactive oxides,this approach directly generates a unique composite film consisting of NiFe layered oxyhydroxides and amorphous oxides,exhibiting an overpotential as small as 255 mV(10 mA cm^(−2))and a turnover frequency of∼0.4 s^(−1)per metal atom.By using such a facile protocol,the surface rate-limiting issue of BiVO_(4)photoanodes can be effectively resolved,resulting in a charge injection efficiency of over 90%.Considering this deposition directly start from simple nitrates but only takes several seconds to complete,we believe it can be developed as a widely applicable and welcomed functionalization technique for diverse electrochemical devices.展开更多
In this study we report a series of nickel-rich layered cathodes LiNi1-2xCoxMnxO2(x = 0.075, 0.05,0.025) prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are su...In this study we report a series of nickel-rich layered cathodes LiNi1-2xCoxMnxO2(x = 0.075, 0.05,0.025) prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are submicron-sized particles and the particle sizes increase with the increase of Ni content.LiNi0.85Co0.075Mn0.075O2 delivers a discharge capacity of 174.9 mAh g-1 with holding 93% reversible capacity at 1 C after 80 cycles, and can maintain a discharge capacity of 175.3 mAh g-1 at 5 C rate. With increasing Ni content, the initial specific capacity increases while the cycling and rate performance degrades in some extent. These satisfying results demonstrate that spray pyrolysis is a powerful and efficient synthesis technology for producing Ni-rich layered cathode(Ni content 〉 80%).展开更多
Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set ...Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set temperature, concentration of AgNO3 aqueous solution, flux of AgNO3 aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO3 aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO3 aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO3 solutions, 336 mL/h flux of AgNO3 aqueous solution, 0.32 MPa flux of carrier gas at 720 ℃ furnace set temperature.展开更多
Fluorine doped tin oxide, SnO2:F, thin films were deposited by ultrasonic chemical spray starting from tin chloride and hydrofluoric acid. The physical characteristics of the films as a function of both water content ...Fluorine doped tin oxide, SnO2:F, thin films were deposited by ultrasonic chemical spray starting from tin chloride and hydrofluoric acid. The physical characteristics of the films as a function of both water content in the starting solution and substrate temperature were studied. The film structure was polycrystalline in all cases, showing that the intensity of (200) peak increased with the water content in the starting solution. The electrical resistivity decreased with the water content, reaching a minimum value, in the order of 8 × 10-4 Ωcm, for films deposited at 450℃ from a starting solution with a water content of 10 ml per 100 ml of solution;further increase in water content increased the corresponding resistivity. Optical transmittances of SnO2:F films were high, in the order of 75%, and the band gap values oscillated around 3.9 eV. SEM analysis showed uniform surface morphologies with different geometries depending on the deposition conditions. Composition analysis showed a stoichiometric compound with a [Sn/O] ratio around 1:2 in all samples. The presence of F into the SnO2 lattice was detected, within 2 at % respect to Sn.展开更多
The Pr and Ta separately doped FTO(10 at.% F incorporated Sn O2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO(FTO) films are inv...The Pr and Ta separately doped FTO(10 at.% F incorporated Sn O2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO(FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction(XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has(200) preferential orientation, but this orientation changes to(211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy(AFM) and scanning electron microscopy(SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible(UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.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
Highly transparent conductive stoichiometric nanocrystalline stannic oxide coatings were deposited onto Corning®EAGLE XG®slim glass substrates.Including each coating,it was deposited for various concentratio...Highly transparent conductive stoichiometric nanocrystalline stannic oxide coatings were deposited onto Corning®EAGLE XG®slim glass substrates.Including each coating,it was deposited for various concentrations in the aerosol solution with the substrate temperature maintained at 623.15 K by an ultrasonic spray pyrolysis(USP)technique.Nitrogen was em-ployed both as the solution carrier in addition to aerosol directing gas,maintaining its flow rates at 3500.0 and 500.0 mL/min,respectively.The coatings were polycrystalline,with preferential growth along the stannic oxide(112)plane,irrespective of the molarity content in the spray solution.The coating prepared at 0.2 M,a concentration in the aerosol solution,showed an average transmission of 60%in the visible light region spectrum with a maximum conductivity of 24.86 S/cm.The coatings deposited exhibited in the general photoluminescence spectrum emission colors of green,greenish white,and bluish white calculated on the intensities of the excitonic and oxygen vacancy defect level emissions.展开更多
Following are the comments for the queries raised by Prof. Pawel E. Tomaszewski on our published paper entitled "Structural, Optical, and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Sp...Following are the comments for the queries raised by Prof. Pawel E. Tomaszewski on our published paper entitled "Structural, Optical, and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Spray Pyrolysis Technique" by K. Usharani and A.R. Balu published in Acta Metall. Sin.展开更多
CeO_(2) is one of the main catalysts for solid oxide fuel cell(SOFC).It is critical to find a green and costeffective fabrication method for CeO_(2) at scale.In this study,the CeO_(2) microspheres were prepared by one...CeO_(2) is one of the main catalysts for solid oxide fuel cell(SOFC).It is critical to find a green and costeffective fabrication method for CeO_(2) at scale.In this study,the CeO_(2) microspheres were prepared by one-step ultrasonic spray pyrolysis of cerium chloride solution at700℃.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)study demonstrate that the prepared CeO_(2) microspheres exhibit a particle size of0.01-1.08μm with a mean particle size of 0.23μm,and more than 94%of the particles have a diameter less than0.5μm.But the presence of residual Cl in the fabricated CeO_(2) microspheres blocks the active sites and leads to the significant degradation of SOFC performance.The formation mechanism and distribution of residual Cl in the fabricated CeO_(2) microspheres were systemic ally studied.The water washing method was shown to effectively reduce the residual Cl in the CeO_(2) microspheres.Overall,this work provides a clean manufacturing process for the preparation of SOFC electrode/electrolyte materials.展开更多
A novel rapid and continuous process has developed for the synthesis of nitrogen-doped TiO2(N-TiO2)with flame spray pyrolysis(FSP) method. The nitrogen incorporation into TiO2 was achieved by a facile modification...A novel rapid and continuous process has developed for the synthesis of nitrogen-doped TiO2(N-TiO2)with flame spray pyrolysis(FSP) method. The nitrogen incorporation into TiO2 was achieved by a facile modification(addition of dilute nitric acid) in the precursor for the synthesis. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The doping of nitrogen into the TiO2 was confirmed by X-ray photoelectron spectroscopy(XPS) and energy dispersive X-ray(EDX) spectroscopy. The UV-vis spectra of the modified catalysts(with primary N source) exhibited band-gap narrowing for 4 N-TiO2 with band gap energy of 2.89 eV, which may be due to the presence of nitrogen in TiO2 structure. The introduction of secondary N-source(urea) into TiO2 crystal lattice results in additional reduction of the band gap energy to 2.68 eV and shows a significant improvement of visible light absorption. The N-TiO2 nanoparticles modified by using secondary N-source showed significant photocatalytic activity under visible light much higher than TiO2. The higher activity is attributed to the synergetic interaction of nitrogen with the TiO2 lattice. The lowering of the band-gap energy for the flame made N-doped TiO2 materials implies that the nitrogen doping in TiO2 by aerosol method is highly effective in extending the optical response of TiO2 in the visible region. The nitrogen atomic percentage has increased monotonically(0.09%-0.15%)with the increase in primary nitrogen source(nitric acid), and significantly boosted to 0.97% when secondary nitrogen source(urea) was introduced. The highest rate of phenol degradation was obtained for catalysts with secondary N source due to increase in N content in the catalyst.展开更多
LiVPO4F suffers problems of difficulty in synthesis and poor conductivity. To solve these,herein sub-micro spherical LiVPO4F/C is synthesized from a highly-reactive hollow VPO4/C sphere that is derived from a facile a...LiVPO4F suffers problems of difficulty in synthesis and poor conductivity. To solve these,herein sub-micro spherical LiVPO4F/C is synthesized from a highly-reactive hollow VPO4/C sphere that is derived from a facile and fast spray pyrolysis for the first time. Uniform carbon coating layer with a thickness of 5–8 nm is observed on the surface of the particles,helping to improve the electronic conductivity,suppress the particle growth and protect the particles from corrosion by the electrolyte. The particles are shaped as fine sub-micro spheres,which are beneficial for shortening the distance for Li+ transport. Rietveld refinement for the X-ray diffraction pattern of as-prepared sample shows high-purity triclinic LiVPO4F with an enlarged lattice volume,enabling faster Li+ transport in the prepared material. Accordingly,the resulted LiVPO4F/C demonstrates superior electrochemical properties,delivering 135.4,91.1 mA hg-1 at 1,40 C respectively,and remaining the capacity of 93.3 mA hg-1 after 500 cycles at 20 C with the retention of 95.0%. The method introduced here provides an efficient way to address the serious problems of preparing high-purity Li VPO4F with good conductivity.展开更多
Fe-doped ZnO thin films have been prepared by spray pyrolysis on glass substrates and the influence of Fe-doping concentration on the structural and optical properties of the films has been studied.The X-ray diffracti...Fe-doped ZnO thin films have been prepared by spray pyrolysis on glass substrates and the influence of Fe-doping concentration on the structural and optical properties of the films has been studied.The X-ray diffraction (XRD) analysis shows that Fe doping has a significant effect on crystalline quality,grain size and strain in the thin films.The best crystalline structure is obtained for 3 at%Fe doping as observed from scanning electron microscopy (SEM) and XRD.However,lower or higher Fe-doping degrades the crystalline quality in turn.Moreover,UV spectroscopy demonstrates the influence of Fe-incorporation on visible range transmittance of ZnO where the best transmittance is obtained for 3 at%doping.The results have been illustrated simultaneously focusing previous results obtained from literature.展开更多
The particle formation mechanism of hydroxyapatite precursor containing two components, Ca(OOCCH3)2 and (NH4)2HPO4 with a ratio of Ca/P = 1.67, in a spray pyrolysis process has been studied by computational fluid ...The particle formation mechanism of hydroxyapatite precursor containing two components, Ca(OOCCH3)2 and (NH4)2HPO4 with a ratio of Ca/P = 1.67, in a spray pyrolysis process has been studied by computational fluid dynamics (CFD) simulation on the transfer of heat and mass from droplets to the surrounding media. The focus included the evaporation of the solvent in the droplets, a second evaporation due to crust formation, the decomposition reaction of each component of the precursor, and a solid-state reaction that included the kinetic parameters of the precursor regarding its two components that formed the hydroxyapatite product. The rate of evaporation and the reacted fraction of the precursor both increased with temperature. The predicted average size of the hydroxyapatite particles agreed well with the experimental results. Therefore, the selected models were also suitable for predicting the average size of particles that contain two components in the precursor solution.展开更多
Hollow A1203 nanospheres with well-defined structure and shape were successfully prepared via flame spray pyrolysis (FSP) in the presence of a surfactant as droplet stabilizer. The morphology and structure of the na...Hollow A1203 nanospheres with well-defined structure and shape were successfully prepared via flame spray pyrolysis (FSP) in the presence of a surfactant as droplet stabilizer. The morphology and structure of the nanospheres were systematically characterized by transmission electron microscopy, scanning electron microscopy, and N2 sorption. A solution of hydrated aluminum nitrate, polyethylene glycol (PEG) and absolute ethanol was sprayed into a flame to transform droplets into particles after evaporation and surface nucleation, forming hollow AI203 nanospheres from aluminum nitrate decomposition. The surfactant was found effective in producing smaller droplets because of decreased surface tension and viscosity, while the combination of oxygen atoms on PEG chains and aluminum ions in solution reduced interfacial turbulence, leading to increased stability of the droplets.展开更多
Tin sulfide thin films (Snx Sy) with an atomic ratio of y/x = 0.5 have been deposited on a glass substrate by spray pyrolysis. The effects of deposition parameters, such as spray solution rate (R), substrate tempe...Tin sulfide thin films (Snx Sy) with an atomic ratio of y/x = 0.5 have been deposited on a glass substrate by spray pyrolysis. The effects of deposition parameters, such as spray solution rate (R), substrate temperature (Ts) and film thickness (t), on the structural, optical, thermo-electrical and photoconductivity related properties of the films have been studied. The precursor solution was prepared by dissolving tin chloride (SnC14, 5H2O) and thiourea in propanol, and SnxSy thin film was prepared with a mole ratio of y/x = 0.5. The prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. It is indicated that the XRD patterns of SnxSy films have amorphous and polycrystalline structures and the size of the grains has been changed from 7 to 16 nm. The optical gap of SnxSy thin films is determined to be about 2.41 to 3.08 eV by a plot of the variation of (αhv)2 versus h v related to the change of deposition conditions. The thermoelectric and photo-conductivity measurement results for the films show that these properties are depend considerably on the deposition parameters.展开更多
An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by ...An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe method.FES EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content varies.XRD studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping concentrations.The grain size is found to decrease with the increase in Fe content.These studies also specify that the films have tetragonal rutile-type structure with mixed secondary phases.The texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping concentrations.The resistivity and the optical absorbance are found to increase with Fe concentration.The direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.展开更多
Porous hollow Co3O4 microspheres have been synthesized from a mixed cobalt nitrate and urea solution through spray pyrolysis followed by calcination at 600 ℃ in air. This porous hollow Co3O4 is assembled by nanoparti...Porous hollow Co3O4 microspheres have been synthesized from a mixed cobalt nitrate and urea solution through spray pyrolysis followed by calcination at 600 ℃ in air. This porous hollow Co3O4 is assembled by nanoparticles and exhibits variable porosity depending on the amount of gas in the system. In pyrolysis process, urea continuously decomposes into gaseous components, which act as a template to control the porous structure. The amount of gas escaping from precursor droplets can directly influence the porosity of the microspheres and the size of the nanoparticles controlled by the ratio of urea to cobalt nitrate. Electrochemical measurements show that the performance of the porous hollow Co3O4 microspheres is related to the porosity and size of the nanopartides. The sample with optimal porosity delivers a high first charge capacity of 1,417.9 mAh·g^-1 at 0.2C (1C = 890 mA·g^-1), and superior charge cycle performance of 1,012.7 mAh.g-1 after 100 cycles. In addition, the optimized material displays satisfactory rate performance of 1,012.4 mAh.g-1 at 1C after 50 cycles and 881.3 mAh·g^-1 at 2C after 300 cycles. Superior charge/discharge capacity, excellent rate performance and high yield achieved in this study is promising for the development of high-performance Co3O4 anode materials for lithium-ion batteries.展开更多
基金Project supported by National "The Tenth Five-Year"plan (2003BA316A01-03-05) and "The Tenth Five-Year"Plan(BE2004021) of Jiangsu provicce
文摘Spherical YAG:Ce^3+ phosphor particles with narrow size distribution were prepared by spray pyrolysis. The effects of the concentration of solution, the flow rate of cartier gas and the annexing temperature on the phosphor morphology were studied. The productivity of precursor particles shows a trend of drop after rising with the increase of concentration Raising the flow rate of nitrogen can improve the productivity of the precursor particles. Phosphor prepared by spray pyrolysis has obviously higher emission intensity than that synthesized by solid state reaction, spray pyrolysis makes Ce^3+ ions well distributed in the crystal lattice as the luminescent centers, and phosphor particles have regular sphericity and narrow size distribution.
文摘Boron-doped NiO thin films were prepared on glass substrates at 400℃ by airbrush spraying method using a solution of nickel nitrate hexahydrate. Their physical properties were investigated as a function of dopant concentration. From X-ray diffraction patterns, it is observed that the films have cubic structure with lattice parameters varying with boron concentration. The morphologies of the films were examined by using scanning electron microscopy, and the grain sizes were measured to be around 30-50 nm. Optical measurements show that the band gap energies of the films first decrease then increase with increasing boron concentration. The resistivities of the films were determined by four point probe method, and the changes in resistivity with boron concentration were investigated.
基金financially supported by the Scientific and Technological Research Council of Turkey (No. 107M505)
文摘ZnO nanoparticles and porous particles were produced by an ultrasonic spray pyrolysis method using a zinc nitrate precursor at various temperatures under air atmosphere. The effects of reaction temperature on the size and morphology of ZnO particles were investi- gated. The samples were characterized by energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. ZnO particles were obtained in a hexagonal crystal structure and the crystallite shapes changed from spherical to hex- agonal by elevating the reaction temperature. The crystallite size grew by increasing the temperature, in spite of reducing the residence time in the heated zone. ZnO nanoparticles were obtained at the lowest reaction temperature and ZnO porous particles, formed by aggregation of ZnO nanoparticles due to effective sintering, were prepared at higher temperatures. The results showed that the properties of ZnO particles can be controlled by changing the reaction temperature in the ultrasonic spray pyrolysis method.
基金financially supported by the National Natural Science Foundation of China(NSFC,21805298,21905288,51904288)the Zhejiang Provincial Natural Science Foundation(Z21B030017)+2 种基金the K.C.Wong Education Foundation(GJTD-201913)the Ningbo major special projects of the Plan‘‘Science and Technology Innovation 2025”(2018B10056,2019B10046)the Ningbo 3315 Program。
文摘The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge.However,there is a lack of facile techniques for depositing compact catalytic films of high coverage and possessing a state-of-the-art performance,which is especially desired in photoelectrochemical(PEC)systems.Herein,we demonstrate a spray pyrolysis(SP)route to address this issue,featuring the kinetic selective preparation towards the desired catalytic-active material.Differing from reported SP protocols which only produce inactive oxides,this approach directly generates a unique composite film consisting of NiFe layered oxyhydroxides and amorphous oxides,exhibiting an overpotential as small as 255 mV(10 mA cm^(−2))and a turnover frequency of∼0.4 s^(−1)per metal atom.By using such a facile protocol,the surface rate-limiting issue of BiVO_(4)photoanodes can be effectively resolved,resulting in a charge injection efficiency of over 90%.Considering this deposition directly start from simple nitrates but only takes several seconds to complete,we believe it can be developed as a widely applicable and welcomed functionalization technique for diverse electrochemical devices.
基金financial support of the National Basic Research Program of China (2014CB643406)the National Natural Science Foundation of China (51674296, 51704332)+1 种基金the National Postdoctoral Program for Innovative Talents (BX201700290)the Fundamental Research Funds for the Central Universities of Central South University (2017zzts125)
文摘In this study we report a series of nickel-rich layered cathodes LiNi1-2xCoxMnxO2(x = 0.075, 0.05,0.025) prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are submicron-sized particles and the particle sizes increase with the increase of Ni content.LiNi0.85Co0.075Mn0.075O2 delivers a discharge capacity of 174.9 mAh g-1 with holding 93% reversible capacity at 1 C after 80 cycles, and can maintain a discharge capacity of 175.3 mAh g-1 at 5 C rate. With increasing Ni content, the initial specific capacity increases while the cycling and rate performance degrades in some extent. These satisfying results demonstrate that spray pyrolysis is a powerful and efficient synthesis technology for producing Ni-rich layered cathode(Ni content 〉 80%).
文摘Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set temperature, concentration of AgNO3 aqueous solution, flux of AgNO3 aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO3 aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO3 aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO3 solutions, 336 mL/h flux of AgNO3 aqueous solution, 0.32 MPa flux of carrier gas at 720 ℃ furnace set temperature.
基金This work was partially supported by CONACyT under contract Number 166601.
文摘Fluorine doped tin oxide, SnO2:F, thin films were deposited by ultrasonic chemical spray starting from tin chloride and hydrofluoric acid. The physical characteristics of the films as a function of both water content in the starting solution and substrate temperature were studied. The film structure was polycrystalline in all cases, showing that the intensity of (200) peak increased with the water content in the starting solution. The electrical resistivity decreased with the water content, reaching a minimum value, in the order of 8 × 10-4 Ωcm, for films deposited at 450℃ from a starting solution with a water content of 10 ml per 100 ml of solution;further increase in water content increased the corresponding resistivity. Optical transmittances of SnO2:F films were high, in the order of 75%, and the band gap values oscillated around 3.9 eV. SEM analysis showed uniform surface morphologies with different geometries depending on the deposition conditions. Composition analysis showed a stoichiometric compound with a [Sn/O] ratio around 1:2 in all samples. The presence of F into the SnO2 lattice was detected, within 2 at % respect to Sn.
文摘The Pr and Ta separately doped FTO(10 at.% F incorporated Sn O2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO(FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction(XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has(200) preferential orientation, but this orientation changes to(211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy(AFM) and scanning electron microscopy(SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible(UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.
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the financial support from the Escuela Superior de Medicina,Instituto Politécnico Nacional,through Project No.20210385。
文摘Highly transparent conductive stoichiometric nanocrystalline stannic oxide coatings were deposited onto Corning®EAGLE XG®slim glass substrates.Including each coating,it was deposited for various concentrations in the aerosol solution with the substrate temperature maintained at 623.15 K by an ultrasonic spray pyrolysis(USP)technique.Nitrogen was em-ployed both as the solution carrier in addition to aerosol directing gas,maintaining its flow rates at 3500.0 and 500.0 mL/min,respectively.The coatings were polycrystalline,with preferential growth along the stannic oxide(112)plane,irrespective of the molarity content in the spray solution.The coating prepared at 0.2 M,a concentration in the aerosol solution,showed an average transmission of 60%in the visible light region spectrum with a maximum conductivity of 24.86 S/cm.The coatings deposited exhibited in the general photoluminescence spectrum emission colors of green,greenish white,and bluish white calculated on the intensities of the excitonic and oxygen vacancy defect level emissions.
文摘Following are the comments for the queries raised by Prof. Pawel E. Tomaszewski on our published paper entitled "Structural, Optical, and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Spray Pyrolysis Technique" by K. Usharani and A.R. Balu published in Acta Metall. Sin.
基金financially supported by the National Key R&D Program of China(No.2018YFB1502600)the National Natural Science Foundation of China(Nos.51922042 and 51872098)+1 种基金China Postdoctoral Science Foundation(No.2019M652888)the Sino-Singapore International Joint Research Institute(SSIJRI),China。
文摘CeO_(2) is one of the main catalysts for solid oxide fuel cell(SOFC).It is critical to find a green and costeffective fabrication method for CeO_(2) at scale.In this study,the CeO_(2) microspheres were prepared by one-step ultrasonic spray pyrolysis of cerium chloride solution at700℃.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)study demonstrate that the prepared CeO_(2) microspheres exhibit a particle size of0.01-1.08μm with a mean particle size of 0.23μm,and more than 94%of the particles have a diameter less than0.5μm.But the presence of residual Cl in the fabricated CeO_(2) microspheres blocks the active sites and leads to the significant degradation of SOFC performance.The formation mechanism and distribution of residual Cl in the fabricated CeO_(2) microspheres were systemic ally studied.The water washing method was shown to effectively reduce the residual Cl in the CeO_(2) microspheres.Overall,this work provides a clean manufacturing process for the preparation of SOFC electrode/electrolyte materials.
基金the U.S. EPA/Pegasus contract (contract number EP-C-11-006) for financial support of this work through the scholarship to Siva Nagi Reddy Inturi
文摘A novel rapid and continuous process has developed for the synthesis of nitrogen-doped TiO2(N-TiO2)with flame spray pyrolysis(FSP) method. The nitrogen incorporation into TiO2 was achieved by a facile modification(addition of dilute nitric acid) in the precursor for the synthesis. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The doping of nitrogen into the TiO2 was confirmed by X-ray photoelectron spectroscopy(XPS) and energy dispersive X-ray(EDX) spectroscopy. The UV-vis spectra of the modified catalysts(with primary N source) exhibited band-gap narrowing for 4 N-TiO2 with band gap energy of 2.89 eV, which may be due to the presence of nitrogen in TiO2 structure. The introduction of secondary N-source(urea) into TiO2 crystal lattice results in additional reduction of the band gap energy to 2.68 eV and shows a significant improvement of visible light absorption. The N-TiO2 nanoparticles modified by using secondary N-source showed significant photocatalytic activity under visible light much higher than TiO2. The higher activity is attributed to the synergetic interaction of nitrogen with the TiO2 lattice. The lowering of the band-gap energy for the flame made N-doped TiO2 materials implies that the nitrogen doping in TiO2 by aerosol method is highly effective in extending the optical response of TiO2 in the visible region. The nitrogen atomic percentage has increased monotonically(0.09%-0.15%)with the increase in primary nitrogen source(nitric acid), and significantly boosted to 0.97% when secondary nitrogen source(urea) was introduced. The highest rate of phenol degradation was obtained for catalysts with secondary N source due to increase in N content in the catalyst.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51704332,51874360 and 51804344)the Program of Huxiang Young Talents(Grant No.2019RS2002)the Innovation and Entrepreneurship Project of Hunan Province,China(Grant No.2018GK5026)。
文摘LiVPO4F suffers problems of difficulty in synthesis and poor conductivity. To solve these,herein sub-micro spherical LiVPO4F/C is synthesized from a highly-reactive hollow VPO4/C sphere that is derived from a facile and fast spray pyrolysis for the first time. Uniform carbon coating layer with a thickness of 5–8 nm is observed on the surface of the particles,helping to improve the electronic conductivity,suppress the particle growth and protect the particles from corrosion by the electrolyte. The particles are shaped as fine sub-micro spheres,which are beneficial for shortening the distance for Li+ transport. Rietveld refinement for the X-ray diffraction pattern of as-prepared sample shows high-purity triclinic LiVPO4F with an enlarged lattice volume,enabling faster Li+ transport in the prepared material. Accordingly,the resulted LiVPO4F/C demonstrates superior electrochemical properties,delivering 135.4,91.1 mA hg-1 at 1,40 C respectively,and remaining the capacity of 93.3 mA hg-1 after 500 cycles at 20 C with the retention of 95.0%. The method introduced here provides an efficient way to address the serious problems of preparing high-purity Li VPO4F with good conductivity.
文摘Fe-doped ZnO thin films have been prepared by spray pyrolysis on glass substrates and the influence of Fe-doping concentration on the structural and optical properties of the films has been studied.The X-ray diffraction (XRD) analysis shows that Fe doping has a significant effect on crystalline quality,grain size and strain in the thin films.The best crystalline structure is obtained for 3 at%Fe doping as observed from scanning electron microscopy (SEM) and XRD.However,lower or higher Fe-doping degrades the crystalline quality in turn.Moreover,UV spectroscopy demonstrates the influence of Fe-incorporation on visible range transmittance of ZnO where the best transmittance is obtained for 3 at%doping.The results have been illustrated simultaneously focusing previous results obtained from literature.
文摘The particle formation mechanism of hydroxyapatite precursor containing two components, Ca(OOCCH3)2 and (NH4)2HPO4 with a ratio of Ca/P = 1.67, in a spray pyrolysis process has been studied by computational fluid dynamics (CFD) simulation on the transfer of heat and mass from droplets to the surrounding media. The focus included the evaporation of the solvent in the droplets, a second evaporation due to crust formation, the decomposition reaction of each component of the precursor, and a solid-state reaction that included the kinetic parameters of the precursor regarding its two components that formed the hydroxyapatite product. The rate of evaporation and the reacted fraction of the precursor both increased with temperature. The predicted average size of the hydroxyapatite particles agreed well with the experimental results. Therefore, the selected models were also suitable for predicting the average size of particles that contain two components in the precursor solution.
基金supported by the National Natural Science Foundation of China (20925621, 20706015, 50703009, 20906027,20906021, 20976054, and 20973059)the Program of Shanghai Subject Chief Scientist (08XD1401500)+4 种基金the Shanghai Shuguang Scholars Tracking Program (08GG09)the Shanghai Rising-Star Program (09QH1400700 and 09QA1401500)the Special Projects for Key Laboratories in Shanghai (09DZ2202000)the Special Projects for Nanotechnology of Shanghai (0852nm02000,0952nm02000, and 0952nm02100)the Shanghai Pujiang Program (09PJ1403200)
文摘Hollow A1203 nanospheres with well-defined structure and shape were successfully prepared via flame spray pyrolysis (FSP) in the presence of a surfactant as droplet stabilizer. The morphology and structure of the nanospheres were systematically characterized by transmission electron microscopy, scanning electron microscopy, and N2 sorption. A solution of hydrated aluminum nitrate, polyethylene glycol (PEG) and absolute ethanol was sprayed into a flame to transform droplets into particles after evaporation and surface nucleation, forming hollow AI203 nanospheres from aluminum nitrate decomposition. The surfactant was found effective in producing smaller droplets because of decreased surface tension and viscosity, while the combination of oxygen atoms on PEG chains and aluminum ions in solution reduced interfacial turbulence, leading to increased stability of the droplets.
文摘Tin sulfide thin films (Snx Sy) with an atomic ratio of y/x = 0.5 have been deposited on a glass substrate by spray pyrolysis. The effects of deposition parameters, such as spray solution rate (R), substrate temperature (Ts) and film thickness (t), on the structural, optical, thermo-electrical and photoconductivity related properties of the films have been studied. The precursor solution was prepared by dissolving tin chloride (SnC14, 5H2O) and thiourea in propanol, and SnxSy thin film was prepared with a mole ratio of y/x = 0.5. The prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. It is indicated that the XRD patterns of SnxSy films have amorphous and polycrystalline structures and the size of the grains has been changed from 7 to 16 nm. The optical gap of SnxSy thin films is determined to be about 2.41 to 3.08 eV by a plot of the variation of (αhv)2 versus h v related to the change of deposition conditions. The thermoelectric and photo-conductivity measurement results for the films show that these properties are depend considerably on the deposition parameters.
文摘An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe method.FES EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content varies.XRD studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping concentrations.The grain size is found to decrease with the increase in Fe content.These studies also specify that the films have tetragonal rutile-type structure with mixed secondary phases.The texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping concentrations.The resistivity and the optical absorbance are found to increase with Fe concentration.The direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.
基金This work was supported by the National Natural Science Foundation of China (NSFC) (Nos. 21471006 and 21271009), the Programs for Science and Technology Development of Anhui Province (No. 1501021019), the Recruitment Program for Leading Talent Team of Anhui Province, the Program for Innova- tive Research Team of Anhui Education Committee, and the Research Foundation for Science and Technology Leaders and Candidates of Anhui Province.
文摘Porous hollow Co3O4 microspheres have been synthesized from a mixed cobalt nitrate and urea solution through spray pyrolysis followed by calcination at 600 ℃ in air. This porous hollow Co3O4 is assembled by nanoparticles and exhibits variable porosity depending on the amount of gas in the system. In pyrolysis process, urea continuously decomposes into gaseous components, which act as a template to control the porous structure. The amount of gas escaping from precursor droplets can directly influence the porosity of the microspheres and the size of the nanoparticles controlled by the ratio of urea to cobalt nitrate. Electrochemical measurements show that the performance of the porous hollow Co3O4 microspheres is related to the porosity and size of the nanopartides. The sample with optimal porosity delivers a high first charge capacity of 1,417.9 mAh·g^-1 at 0.2C (1C = 890 mA·g^-1), and superior charge cycle performance of 1,012.7 mAh.g-1 after 100 cycles. In addition, the optimized material displays satisfactory rate performance of 1,012.4 mAh.g-1 at 1C after 50 cycles and 881.3 mAh·g^-1 at 2C after 300 cycles. Superior charge/discharge capacity, excellent rate performance and high yield achieved in this study is promising for the development of high-performance Co3O4 anode materials for lithium-ion batteries.