Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and ...Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water(SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20—70℃ proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.展开更多
A simple sonochemical route for the surface coating of titanium dioxide on cadmium sulfide nanocrystal was reported. After 2 h ultrasonic irradiation treatment, the mixture of CdS nanocrystals and tetrabutyl titanate ...A simple sonochemical route for the surface coating of titanium dioxide on cadmium sulfide nanocrystal was reported. After 2 h ultrasonic irradiation treatment, the mixture of CdS nanocrystals and tetrabutyl titanate in an aqueous medium yielded CdS/TiO2 nanocrystals composites with core/shell structure. The thickness of TiO2 layer with smooth interface could be easily controlled via changing the concentration of the precursors and the time of irradiation. The core/shell nanocrysrals were characterized by X-ray diffraction, transmission electron microscope and UV-vis spectrometry techniques. The prepared semiconductor composites with particular band structure present appealing properties especially in photochemical activity.展开更多
Semiconductor CdS nanoparticles were synthesized by the sonochemical reduction of a mixed aqueous solution of CdCl2, Na2S2O3 and (CH3)CHOH in Ar atmosphere at room temperature. The results of a detailed investigation ...Semiconductor CdS nanoparticles were synthesized by the sonochemical reduction of a mixed aqueous solution of CdCl2, Na2S2O3 and (CH3)CHOH in Ar atmosphere at room temperature. The results of a detailed investigation with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrum and optical absorption spec-troscopy are reported. A clearly red shift of the absorption edge and a broad absorption band related to the surface states of nanoparticles have been observed in the optical absorption spectra with the increasing of CdS particle size. The mechanisms of the CdS nanoparticle formation and size growth during sonochemical irradiation were discussed. This convenient method is found to be an efficient way to produce other chalcogenides as well.展开更多
ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission elect...ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission electron microscopy（TEM）, Raman spectroscopy, and Fourier transform infrared spectroscopy（FTIR）. In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue（MB） under ultraviolet–visible（UV） light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.展开更多
Self-assembled nanorod of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity sonochemical technique. The synthesized materials were characterized by X-ray diffraction （XRD）, scanning e...Self-assembled nanorod of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity sonochemical technique. The synthesized materials were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and temperature-programmed reduction （TPR） in H2. Catalytic behaviour of the materials over anaerobic n-butane oxidation was studied through temperature-programmed reaction （TPRn）. Catalytic evaluation of the sonochemical treated V2O5 products was also studied on microreactor. XRD patterns of all the vanadium samples were perfectly indexed to V2O5. The morphologies of the nanorod vanadium oxides as shown in SEM and TEM depended on the duration of the ultrasound irradiation. Prolonging the ultrasound irradiation duration resulted in materials with uniform, well defined shapes and surface structures and smaller size of nanorod vanadium oxide bundles. H2-TPR profiles showed that larger amount of oxygen species were removed from the nanorod V2O5 compared to the bulk. Furthermore, the nanorod vanadium oxide bundles, which were produced after 90, 120 and 180 min of sonochemical treatment, showed an additional reduction peak at lower temperature （-850 K）, suggesting the presence of some highly active oxygen species. TPRn in n-butane/He over these materials showed that the nanorod V2O5 with highly active oxygen species showed markedly higher activity than the bulk material, which was further proven by catalytic oxidation of n-butane.展开更多
In recent years,nanostructured photocatalysts have become the research focus due to their immense potential application in environmental purification and energy conversion.The photocatalytic performance of photocataly...In recent years,nanostructured photocatalysts have become the research focus due to their immense potential application in environmental purification and energy conversion.The photocatalytic performance of photocatalysts is closely related to their synthesis methods.High-intensity ultrasound irradiation could provide a unique tool for fabrication of photocatalysts with novel nanostructures.Ultrasound induces acoustic cavitation which generates unique physicochemical conditions,e.g.,hot spot（5000℃）,high pressure of 100 MPa,fast rate of heat conduction（〉〉1×10^10℃·s^-1）.These unique physicochemical conditions allow for the synthesis of various nanostructured photocatalysts.This review summarized the recent development in fabrication of photocatalysts with special nanostructures and their applications.The typical sonochemical reactors and parameters in sonochemical synthesis are introduced and discussed.Sonochemically prepared structures including nano-/microspheres,one-dimensional（1D） nanorods,two-dimensional（2D） nanosheets（nanoflakes,nanosquares）,noble metal nanoparticle（NP）-deposited and element-doped photocatalysts are described and summarized.It is believed that sonication is a green methodology,and it holds greatpotential in the near future for nanostructured photocatalyst fabrication.展开更多
The impact of Ga^(3+)and Gd^(3+)co-substitution on different types of behavior of Ni-Co nanospinel ferrites(NSFs),(Ni_(0.5)Co_(0.5))[Ga_(x)Gd_(x)Fe_(2-2x)]O_(4)(0.000≤x≤0.025),was investigated.NSFs were fabricated t...The impact of Ga^(3+)and Gd^(3+)co-substitution on different types of behavior of Ni-Co nanospinel ferrites(NSFs),(Ni_(0.5)Co_(0.5))[Ga_(x)Gd_(x)Fe_(2-2x)]O_(4)(0.000≤x≤0.025),was investigated.NSFs were fabricated through ultrasound irradiation.The structure,composition,and spherical morphology of all products were verified by numerous characterization techniques such as X-ray diffraction(XRD),scanning and transmission electron microscopes(SEM and TEM),and selected area electron diffraction(SAED).Mossbauer spectra are composed of two ferromagnetic sextets and one paramagnetic doublet.These spectra were fitted to extract hyperfine parameters of the doped samples.Both sublattices'hyperfine magnetic field decreases with substitution.The isomer shift values show that the Mossbauer spectra are composed of magnetic Fe^(3+)sextets.The magnetization measurements at variable magnetic field(M-H)were investigated via a vibrating sample magnetometer(VSM)at temperatures(T)from 300 to 10 K.All NSFs disclose ferrimagnetic behavior at both 300 and 10 K at which they are soft and hard,respectively.We determined that the remanence magnetization(M_(r)),saturation magnetization(M_(s)),and magneton number(n_(B))decrease with increasing Ga^(3+)and Gd^(3+)ions contents.The reduction in these values is predominantly recognized to be the impact of cation redistribution and surface spins on tetrahedral(T_(d))and octahedral(O_(h))sites.As the Ga^(3+)and Gd^(3+)contents increase,the coercivity(H_(c))is also found to decrease.展开更多
The present study deals with the intensified synthesis of starch-polyaniline(starch-PANI)nanocomposite using an ultrasound-assisted method.Starch is a key component in this nanocomposite,which acts as a backbone of th...The present study deals with the intensified synthesis of starch-polyaniline(starch-PANI)nanocomposite using an ultrasound-assisted method.Starch is a key component in this nanocomposite,which acts as a backbone of the nucleation of PANI.The Electrochemical property of the nanocomposite arises due to the addition of PANI.This is one of green approach for the synthesis of bio nanocomposite using ultrasound.The crystallinity of the composite is evaluated using the Scherrer Formula.The starch-PANI nanocomposite was characterized by XRD,FT-IR,Raman,XPS and TEM.The composite nanoparticles show spherical morphology.The elemental composition of starch-PANI showed O 1s peak at 546 eV,N 1s peak at 416 eV,C 1s peak at 286 eV and S 1s peak at 176 eV.The electrochemical studies of the starch-PANI electrodes are evaluated by cyclic voltammetry(CV),galvanostatic charge/discharge(GCD),and electrochemical impedance spectroscopy(EIS).Starch-PANI electrode has shown the maximum specific capacitance of 499.5 F/g at 5 mV/s scan rate.展开更多
The sonochemical decolorization of Methylene Orange was studied using a 24 kHz Ultrasound device with a 1.4 cm diameter horn. pH, power density, the effects of pH and power density on decolorization were discussed. Th...The sonochemical decolorization of Methylene Orange was studied using a 24 kHz Ultrasound device with a 1.4 cm diameter horn. pH, power density, the effects of pH and power density on decolorization were discussed. The combined effect of radiate time, the initial concentration of dyes and the addition of Fe^2＋ on the decolorization was studied using response surface methodology. The results showed that the factorial central composite design was successfully employed for experimental design and predication of the results. AtpH = 2.8, T=30℃, power denstity= 300 W/L and Fe^2＋ of 2 mg/L, the decolorization percentage of 5 mg/L dye solution reached 96% after 60 mill ultreatment. The rate of decolorization of the dye was greatly improved in the presence of Fe^2＋. The sonolysis of the dye followed first-order kinetics.展开更多
A novel, cost effective, sonochemical-hydrothermal technique was used for the deposition of nanosized anatase titanium dioxide (TiO2) onto single wall carbon nanotubes (SWCNTs). This technique is described and the cha...A novel, cost effective, sonochemical-hydrothermal technique was used for the deposition of nanosized anatase titanium dioxide (TiO2) onto single wall carbon nanotubes (SWCNTs). This technique is described and the characterization of the synthesized TiO2-SWCNTs is reported. The characterization techniques employed include scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). From the characterization the size and morphology of the synthesized TiO2 nanoparticles (deposited on the SWCNTs) are reported. Furthermore, it is demonstrated that the created TiO2 nanoparticles are chemically attached to the SWCNTs. Also, an important correlation between calculated TiO2 crystal size and the red shifts in the lowest Raman TiO2 (E.g.) predominate peak is reported. The synthesized TiO2-SWCNTs have potential for large scale production and application in a variety of new technologies such as clean energy power generation devices, electrical storage devices, photocatalysts, and sensors.展开更多
We report a facile approach to synthesize narrow and long graphene nanoribbons (GNRs) by sonochemically cutting chemically derived graphene sheets (GSs). The yield of GNRs can reach ~5 wt% of the starting GSs. The res...We report a facile approach to synthesize narrow and long graphene nanoribbons (GNRs) by sonochemically cutting chemically derived graphene sheets (GSs). The yield of GNRs can reach ~5 wt% of the starting GSs. The resulting GNRs are several micrometers in length, with ~75% being single-layer, and ~40% being narrower than 20 nm in width. A chemical tailoring mechanism involving oxygen-unzipping of GSs under sonochemical conditions is proposed on the basis of experimental observations and previously reported theoretical calculations;it is suggested that the formation and distribution of line faults on graphite oxide and GSs play crucial roles in the formation of GNRs. These results open up the possibilities of the large-scale synthesis and various technological applications of GNRs.展开更多
Graphene oxide(GO)-wrapped gold nanoparticles(Au NPs)hybrid materials are constructed via one-pot sono-chemical synthesis and self-assembly,using ethylene glycol as the reducing agent.The synthesis process above took ...Graphene oxide(GO)-wrapped gold nanoparticles(Au NPs)hybrid materials are constructed via one-pot sono-chemical synthesis and self-assembly,using ethylene glycol as the reducing agent.The synthesis process above took only 1 h,and the obtained hybrid materials exist as spheres wrapped with gauze-like GO sheets via ionic in-teraction-based self-assembly.The GO sheets are helpful for the well dispersion of the Au NPs.Furthermore,these materials possess enhanced photocatalytic activity under visible light irradiation,owing to the synergistic effect of the two components in the hybrid materials.Our work may provide a convenient approach to control the size and morphology of the Au NPs for the synthesis of GO-wrapped hybrid materials,which opens up a feasible way to synthesize metal NPs/GO composites.Moreover,this method might lead to developing of a broad class of new functionalized materials wrapped with GO sheets.展开更多
A simple sonochemical route has been successfully developed to synthesize SnO2 hollow microspheres. The obtained sample is characterized by XRD, TEM, XPS and UV-visible spectrophotometer. The TEM image of the sample a...A simple sonochemical route has been successfully developed to synthesize SnO2 hollow microspheres. The obtained sample is characterized by XRD, TEM, XPS and UV-visible spectrophotometer. The TEM image of the sample at high magnification shows that the shell of the hollow sphere is composed of 3-5 nm SnO2 nanoparticles. A possible formation mechanism of the hollow spheres is briefly discussed.展开更多
The preparation of highly active electrocatalysts with good durability and low cost for fuel cells is highly desir- able but still remains a significant challenge. Here we synthesized two dimensional （2D） C3N4 nanos...The preparation of highly active electrocatalysts with good durability and low cost for fuel cells is highly desir- able but still remains a significant challenge. Here we synthesized two dimensional （2D） C3N4 nanosheets supported palladium composites （C3N4/Pd） via a simple and convenient sonochemical approach. We have systematically stud- ied the electrocatalytic performance of as-prepared catalysts. We found that the prepared C3N4/Pd composites pos- sessed excellent catalytic activity and stability for oxygen reduction reaction （ORR） in alkaline media. Encourag- ingly, the C3N4/Pd catalysts exhibit the excellent electrocatalytic activity for methanol oxidation reaction （MOR） in alkaline media, even better than that of the commercial Pt/C catalyst, The excellent electrocatalytic performance of the 2D C3N4 nanosheets supported palladium composites catalysts results from their synergy effect between the ul- trathin substrate material with large surface area and excellent dispersion of palladium nanoparticles. This study demonstrates that sonochemical method opens up a new avenue for the preparation of electrocatalysts for fuel cells. We expect these materials are likely to find uses in a broad range of applications, for example, fuel cells, solar cells, batteries and other electrochemical analysis.展开更多
A novel sonochemical method is described for the preparation of Fe_(3)O_(4)–TiO_(2)photocatalysts in which nanocrystalline titanium dioxide particles are directly coated onto a magnetic core.The Fe_(3)O_(4)nanopartic...A novel sonochemical method is described for the preparation of Fe_(3)O_(4)–TiO_(2)photocatalysts in which nanocrystalline titanium dioxide particles are directly coated onto a magnetic core.The Fe_(3)O_(4)nanoparticles were partially embedded in TiO_(2)agglomerates.TiO_(2)nanocrystallites were obtained by hydrolysis and condensation of titanium tetraisopropyl in the presence of ethanol and water under high-intensity ultrasound irradiation.This method is attractive since it eliminated the high-temperature heat treatment required in the conventional sol–gel method,which is important in transforming amorphous titanium dioxide into a photoactive crystalline phase.In comparison to other methods,the developed method is simple,mild,green and efficient.The magnetization hysteresis loop for Fe_(3)O_(4)–TiO_(2)nanocomposites indicates that the hybrid catalyst shows superparamagnetic characteristics at room temperature.Photocatalytic activity studies confirmed that the as-prepared nanocomposites have high photocatalytic ability toward the photodegradation of RhB solution.Furthermore,the photodecomposition rate decreases only slightly after six cycles of the photocatalysis experiment.Thus,these Fe_(3)O_(4)–TiO_(2)nanocomposites can be served as an effective and conveniently recyclable photocatalyst.展开更多
Preparation of iron oxide （α-Fe2O3） nanoparticles was carried out via a sonochemical process. The process parameters sucb as temperature, sonication time and power of ultrasonication play important roles in the siz...Preparation of iron oxide （α-Fe2O3） nanoparticles was carried out via a sonochemical process. The process parameters sucb as temperature, sonication time and power of ultrasonication play important roles in the size and morphology of the final products. The iron oxide nanoparticles were characterized by trans- mission electron microscopy, X-ray powder diffraction, and thermogravimetric and differential thermal analyses. From transmission electron microscopy observations, the size of the iron oxide nanoparticles is estimated to be significantly smaller than 19 nm. X-ray diffraction data of the powder after annealing provide direct evidence that the iron oxide was formed during the sonochemical process.展开更多
Tubular metal-organic complex (C2H9N2)2(C2H10N2)0.5[MoO2(OC6H4O)2] has been synthesized. The title complex crystallizes in the tetragonal system, space group P4(2)/n with a = 25.214(8), c = 7.484(4) ?, and Z = 8. The ...Tubular metal-organic complex (C2H9N2)2(C2H10N2)0.5[MoO2(OC6H4O)2] has been synthesized. The title complex crystallizes in the tetragonal system, space group P4(2)/n with a = 25.214(8), c = 7.484(4) ?, and Z = 8. The X-ray structural analysis of the complex reveals tube-like framework which is stabilized by hydrogen bond. Chiral anions [Mo(V)O2(OC6H4O)2]3? of the complex have two types of isomers(λ /δ configuration). Helical nanostructure of this metal-organic complex was formed using a sonochemical method. Sonocation may lead to the transformation from the bulk tubular complex to the helical nanostructure. The as-synthesized nanohelices were all double-stranded and left- and right-handed nanohelices were both formed. The helical nanostructure is a new morphology of inorganic-organic hybrid materials on the nanoscale level and the exact formation mechanism of these helices still needs further investigation.展开更多
This study reports the successful so nochemical synthesis of novel Fe3O4/SiO2/ZnO-Pr6O11(Fe/Si/Zn-Pr6O11) nanocomposites using fructose as a green capping agent.The influence of various parameters containing capping a...This study reports the successful so nochemical synthesis of novel Fe3O4/SiO2/ZnO-Pr6O11(Fe/Si/Zn-Pr6O11) nanocomposites using fructose as a green capping agent.The influence of various parameters containing capping agent,power and time of ultrasound irradiation was investigated to reach optimum morphology and size conditions.The products obtained were characterized by transmission electron microscopy(TEM),UV/Vis diffuse reflectance spectroscopy(DRS),Fourier transform infrared spectra(FT-IR),vibration sample magnetometer(VSM),scanning electron microscopy(SEM),energy dispersive X-ray microanalysis(EDS) and X-ray diffraction(XRD).The Fe3O4/SiO2/ZnO-Pr6O11 nanocomposites display remarkably enhanced photocatalytic activity towards rhodamine b degradation(89.6%)and Congo red(84.7%) under UV irradiation compared with the other products.The results illustrate that the photocatalytic efficiency of magnetic nanocomposites is very much higher than pure Pr6O11nanostructures.Magnetic photocatalyst still has good stability after five successive runs.So,these recyclable nanocomposites can play a role in the treatment of both industrial and domestic contaminated water.展开更多
Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H 2 fuel production.One of the sustainable and efficient techniques is electrocatalytic water split-ting fo...Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H 2 fuel production.One of the sustainable and efficient techniques is electrocatalytic water split-ting for H 2 generation,but it is still restricted by the kinetically sluggish OER.Due to the lower standard oxidation potential of−0.33 V,replacing the OER with anodic hydrazine oxidation reaction(HzOR)is an effective way to extensively reduce the use of electricity in water electrolysis.Through alloying,the semiconductor and adsorption characteristics of Cu,interlaced by Pd 2+solution on the Pd surface by pulsed laser ablation(PLA)in methanol,are selectively altered to maximize cathodic HER and anodic HzOR performance.The optimal Cu1Pd3/C ratio demonstrates outstanding HER performance with a low overpotential of 0.315 V at 10 mA cm^(−2),as well as an ultralow overpotential of 0.560 V for HzOR in 0.5 M N_(2) H_(4)/1.0 M KOH.Furthermore,the constructed HzOR-assisted electrolyzer cell with Cu1Pd3/C||Cu1Pd3/C as anode and cathode exhibits a cell voltage of 0.505 V at 10 mA cm^(−2) with exceptional en-durance over 5 h.The current study advances competent CuPd alloys as multifunctional electrocatalysts for H 2 fuel production using a HzOR-assisted energy-efficient electrolyzer.展开更多
The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical m...The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu^(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu^(3+):Li^+ in solid state display and photocatalytic applications.展开更多
文摘Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water(SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20—70℃ proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.
基金Funded by the National Natural Science Foundation of China (Nos.50532030 and 50625206)the Zhejiang Provincial Natural ScienceFoundation of China (No. Z4080021)
文摘A simple sonochemical route for the surface coating of titanium dioxide on cadmium sulfide nanocrystal was reported. After 2 h ultrasonic irradiation treatment, the mixture of CdS nanocrystals and tetrabutyl titanate in an aqueous medium yielded CdS/TiO2 nanocrystals composites with core/shell structure. The thickness of TiO2 layer with smooth interface could be easily controlled via changing the concentration of the precursors and the time of irradiation. The core/shell nanocrysrals were characterized by X-ray diffraction, transmission electron microscope and UV-vis spectrometry techniques. The prepared semiconductor composites with particular band structure present appealing properties especially in photochemical activity.
基金This work was supported by the National Key Basic Research Project(G1999064501)the Natural Science Foundation of Anhui Province(No.01044903).
文摘Semiconductor CdS nanoparticles were synthesized by the sonochemical reduction of a mixed aqueous solution of CdCl2, Na2S2O3 and (CH3)CHOH in Ar atmosphere at room temperature. The results of a detailed investigation with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrum and optical absorption spec-troscopy are reported. A clearly red shift of the absorption edge and a broad absorption band related to the surface states of nanoparticles have been observed in the optical absorption spectra with the increasing of CdS particle size. The mechanisms of the CdS nanoparticle formation and size growth during sonochemical irradiation were discussed. This convenient method is found to be an efficient way to produce other chalcogenides as well.
基金financially supported by the National Research University Project for Chiang Mai University (CMU) from the Thailand’s Office of the Higher Education Commission, Thailand
文摘ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission electron microscopy（TEM）, Raman spectroscopy, and Fourier transform infrared spectroscopy（FTIR）. In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue（MB） under ultraviolet–visible（UV） light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.
文摘Self-assembled nanorod of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity sonochemical technique. The synthesized materials were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and temperature-programmed reduction （TPR） in H2. Catalytic behaviour of the materials over anaerobic n-butane oxidation was studied through temperature-programmed reaction （TPRn）. Catalytic evaluation of the sonochemical treated V2O5 products was also studied on microreactor. XRD patterns of all the vanadium samples were perfectly indexed to V2O5. The morphologies of the nanorod vanadium oxides as shown in SEM and TEM depended on the duration of the ultrasound irradiation. Prolonging the ultrasound irradiation duration resulted in materials with uniform, well defined shapes and surface structures and smaller size of nanorod vanadium oxide bundles. H2-TPR profiles showed that larger amount of oxygen species were removed from the nanorod V2O5 compared to the bulk. Furthermore, the nanorod vanadium oxide bundles, which were produced after 90, 120 and 180 min of sonochemical treatment, showed an additional reduction peak at lower temperature （-850 K）, suggesting the presence of some highly active oxygen species. TPRn in n-butane/He over these materials showed that the nanorod V2O5 with highly active oxygen species showed markedly higher activity than the bulk material, which was further proven by catalytic oxidation of n-butane.
基金financially supported by the National Natural Science Foundation of China (Nos.21567008 and 21263005)the Young Scientist Training Project of Jiangxi Province China (No.20122BCB23015)+2 种基金Jiangxi Province Natural Science Foundation (No.20133BAB21003)the Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province (No.KJLD14046)Yuan Hang Gongcheng of Jiangxi Province (2014)
文摘In recent years,nanostructured photocatalysts have become the research focus due to their immense potential application in environmental purification and energy conversion.The photocatalytic performance of photocatalysts is closely related to their synthesis methods.High-intensity ultrasound irradiation could provide a unique tool for fabrication of photocatalysts with novel nanostructures.Ultrasound induces acoustic cavitation which generates unique physicochemical conditions,e.g.,hot spot（5000℃）,high pressure of 100 MPa,fast rate of heat conduction（〉〉1×10^10℃·s^-1）.These unique physicochemical conditions allow for the synthesis of various nanostructured photocatalysts.This review summarized the recent development in fabrication of photocatalysts with special nanostructures and their applications.The typical sonochemical reactors and parameters in sonochemical synthesis are introduced and discussed.Sonochemically prepared structures including nano-/microspheres,one-dimensional（1D） nanorods,two-dimensional（2D） nanosheets（nanoflakes,nanosquares）,noble metal nanoparticle（NP）-deposited and element-doped photocatalysts are described and summarized.It is believed that sonication is a green methodology,and it holds greatpotential in the near future for nanostructured photocatalyst fabrication.
文摘The impact of Ga^(3+)and Gd^(3+)co-substitution on different types of behavior of Ni-Co nanospinel ferrites(NSFs),(Ni_(0.5)Co_(0.5))[Ga_(x)Gd_(x)Fe_(2-2x)]O_(4)(0.000≤x≤0.025),was investigated.NSFs were fabricated through ultrasound irradiation.The structure,composition,and spherical morphology of all products were verified by numerous characterization techniques such as X-ray diffraction(XRD),scanning and transmission electron microscopes(SEM and TEM),and selected area electron diffraction(SAED).Mossbauer spectra are composed of two ferromagnetic sextets and one paramagnetic doublet.These spectra were fitted to extract hyperfine parameters of the doped samples.Both sublattices'hyperfine magnetic field decreases with substitution.The isomer shift values show that the Mossbauer spectra are composed of magnetic Fe^(3+)sextets.The magnetization measurements at variable magnetic field(M-H)were investigated via a vibrating sample magnetometer(VSM)at temperatures(T)from 300 to 10 K.All NSFs disclose ferrimagnetic behavior at both 300 and 10 K at which they are soft and hard,respectively.We determined that the remanence magnetization(M_(r)),saturation magnetization(M_(s)),and magneton number(n_(B))decrease with increasing Ga^(3+)and Gd^(3+)ions contents.The reduction in these values is predominantly recognized to be the impact of cation redistribution and surface spins on tetrahedral(T_(d))and octahedral(O_(h))sites.As the Ga^(3+)and Gd^(3+)contents increase,the coercivity(H_(c))is also found to decrease.
基金by the National Institute of Technology,Warangal(NITW)through the Technical Education Quality Improvement Program(TEQIP),MHRD.
文摘The present study deals with the intensified synthesis of starch-polyaniline(starch-PANI)nanocomposite using an ultrasound-assisted method.Starch is a key component in this nanocomposite,which acts as a backbone of the nucleation of PANI.The Electrochemical property of the nanocomposite arises due to the addition of PANI.This is one of green approach for the synthesis of bio nanocomposite using ultrasound.The crystallinity of the composite is evaluated using the Scherrer Formula.The starch-PANI nanocomposite was characterized by XRD,FT-IR,Raman,XPS and TEM.The composite nanoparticles show spherical morphology.The elemental composition of starch-PANI showed O 1s peak at 546 eV,N 1s peak at 416 eV,C 1s peak at 286 eV and S 1s peak at 176 eV.The electrochemical studies of the starch-PANI electrodes are evaluated by cyclic voltammetry(CV),galvanostatic charge/discharge(GCD),and electrochemical impedance spectroscopy(EIS).Starch-PANI electrode has shown the maximum specific capacitance of 499.5 F/g at 5 mV/s scan rate.
文摘The sonochemical decolorization of Methylene Orange was studied using a 24 kHz Ultrasound device with a 1.4 cm diameter horn. pH, power density, the effects of pH and power density on decolorization were discussed. The combined effect of radiate time, the initial concentration of dyes and the addition of Fe^2＋ on the decolorization was studied using response surface methodology. The results showed that the factorial central composite design was successfully employed for experimental design and predication of the results. AtpH = 2.8, T=30℃, power denstity= 300 W/L and Fe^2＋ of 2 mg/L, the decolorization percentage of 5 mg/L dye solution reached 96% after 60 mill ultreatment. The rate of decolorization of the dye was greatly improved in the presence of Fe^2＋. The sonolysis of the dye followed first-order kinetics.
文摘A novel, cost effective, sonochemical-hydrothermal technique was used for the deposition of nanosized anatase titanium dioxide (TiO2) onto single wall carbon nanotubes (SWCNTs). This technique is described and the characterization of the synthesized TiO2-SWCNTs is reported. The characterization techniques employed include scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). From the characterization the size and morphology of the synthesized TiO2 nanoparticles (deposited on the SWCNTs) are reported. Furthermore, it is demonstrated that the created TiO2 nanoparticles are chemically attached to the SWCNTs. Also, an important correlation between calculated TiO2 crystal size and the red shifts in the lowest Raman TiO2 (E.g.) predominate peak is reported. The synthesized TiO2-SWCNTs have potential for large scale production and application in a variety of new technologies such as clean energy power generation devices, electrical storage devices, photocatalysts, and sensors.
基金This work was financially sup-ported by the National Natural Science Foundation of China(Nos.50872136,50972147,and 50921004)and the Chinese Academy of Sciences(No.KJCX2-YW-231).The authors thank Dr.C.Jiang for valuable help on the AFM measurements.
文摘We report a facile approach to synthesize narrow and long graphene nanoribbons (GNRs) by sonochemically cutting chemically derived graphene sheets (GSs). The yield of GNRs can reach ~5 wt% of the starting GSs. The resulting GNRs are several micrometers in length, with ~75% being single-layer, and ~40% being narrower than 20 nm in width. A chemical tailoring mechanism involving oxygen-unzipping of GSs under sonochemical conditions is proposed on the basis of experimental observations and previously reported theoretical calculations;it is suggested that the formation and distribution of line faults on graphite oxide and GSs play crucial roles in the formation of GNRs. These results open up the possibilities of the large-scale synthesis and various technological applications of GNRs.
基金support of the National Natural Sci-ence Foundation of China (No.91023001)the Ministry of Science and Technology of China (National Major Scientific Research Program,No.2011CB932500)the Chinese Academy of Sciences (Knowledge Innovation Program,No.KJCX2-YW-H21)is acknowledged。
文摘Graphene oxide(GO)-wrapped gold nanoparticles(Au NPs)hybrid materials are constructed via one-pot sono-chemical synthesis and self-assembly,using ethylene glycol as the reducing agent.The synthesis process above took only 1 h,and the obtained hybrid materials exist as spheres wrapped with gauze-like GO sheets via ionic in-teraction-based self-assembly.The GO sheets are helpful for the well dispersion of the Au NPs.Furthermore,these materials possess enhanced photocatalytic activity under visible light irradiation,owing to the synergistic effect of the two components in the hybrid materials.Our work may provide a convenient approach to control the size and morphology of the Au NPs for the synthesis of GO-wrapped hybrid materials,which opens up a feasible way to synthesize metal NPs/GO composites.Moreover,this method might lead to developing of a broad class of new functionalized materials wrapped with GO sheets.
文摘A simple sonochemical route has been successfully developed to synthesize SnO2 hollow microspheres. The obtained sample is characterized by XRD, TEM, XPS and UV-visible spectrophotometer. The TEM image of the sample at high magnification shows that the shell of the hollow sphere is composed of 3-5 nm SnO2 nanoparticles. A possible formation mechanism of the hollow spheres is briefly discussed.
基金We greatly appreciate the support of the National Natural Science Foundation of China （Nos. 21475057, 21335004,） and the Program B tbr Outstanding PhD Candidates of Nanjing University. This work was also supported by the Program for New Century Excellent Talents in University （No. NCET-12-0256）.
文摘The preparation of highly active electrocatalysts with good durability and low cost for fuel cells is highly desir- able but still remains a significant challenge. Here we synthesized two dimensional （2D） C3N4 nanosheets supported palladium composites （C3N4/Pd） via a simple and convenient sonochemical approach. We have systematically stud- ied the electrocatalytic performance of as-prepared catalysts. We found that the prepared C3N4/Pd composites pos- sessed excellent catalytic activity and stability for oxygen reduction reaction （ORR） in alkaline media. Encourag- ingly, the C3N4/Pd catalysts exhibit the excellent electrocatalytic activity for methanol oxidation reaction （MOR） in alkaline media, even better than that of the commercial Pt/C catalyst, The excellent electrocatalytic performance of the 2D C3N4 nanosheets supported palladium composites catalysts results from their synergy effect between the ul- trathin substrate material with large surface area and excellent dispersion of palladium nanoparticles. This study demonstrates that sonochemical method opens up a new avenue for the preparation of electrocatalysts for fuel cells. We expect these materials are likely to find uses in a broad range of applications, for example, fuel cells, solar cells, batteries and other electrochemical analysis.
基金support from National Basic Research Program of China(973 Program,Grant No.2007CB936800)SRFDP of China(Project No.20093402110010)are gratefully acknowledged.
文摘A novel sonochemical method is described for the preparation of Fe_(3)O_(4)–TiO_(2)photocatalysts in which nanocrystalline titanium dioxide particles are directly coated onto a magnetic core.The Fe_(3)O_(4)nanoparticles were partially embedded in TiO_(2)agglomerates.TiO_(2)nanocrystallites were obtained by hydrolysis and condensation of titanium tetraisopropyl in the presence of ethanol and water under high-intensity ultrasound irradiation.This method is attractive since it eliminated the high-temperature heat treatment required in the conventional sol–gel method,which is important in transforming amorphous titanium dioxide into a photoactive crystalline phase.In comparison to other methods,the developed method is simple,mild,green and efficient.The magnetization hysteresis loop for Fe_(3)O_(4)–TiO_(2)nanocomposites indicates that the hybrid catalyst shows superparamagnetic characteristics at room temperature.Photocatalytic activity studies confirmed that the as-prepared nanocomposites have high photocatalytic ability toward the photodegradation of RhB solution.Furthermore,the photodecomposition rate decreases only slightly after six cycles of the photocatalysis experiment.Thus,these Fe_(3)O_(4)–TiO_(2)nanocomposites can be served as an effective and conveniently recyclable photocatalyst.
文摘Preparation of iron oxide （α-Fe2O3） nanoparticles was carried out via a sonochemical process. The process parameters sucb as temperature, sonication time and power of ultrasonication play important roles in the size and morphology of the final products. The iron oxide nanoparticles were characterized by trans- mission electron microscopy, X-ray powder diffraction, and thermogravimetric and differential thermal analyses. From transmission electron microscopy observations, the size of the iron oxide nanoparticles is estimated to be significantly smaller than 19 nm. X-ray diffraction data of the powder after annealing provide direct evidence that the iron oxide was formed during the sonochemical process.
文摘Tubular metal-organic complex (C2H9N2)2(C2H10N2)0.5[MoO2(OC6H4O)2] has been synthesized. The title complex crystallizes in the tetragonal system, space group P4(2)/n with a = 25.214(8), c = 7.484(4) ?, and Z = 8. The X-ray structural analysis of the complex reveals tube-like framework which is stabilized by hydrogen bond. Chiral anions [Mo(V)O2(OC6H4O)2]3? of the complex have two types of isomers(λ /δ configuration). Helical nanostructure of this metal-organic complex was formed using a sonochemical method. Sonocation may lead to the transformation from the bulk tubular complex to the helical nanostructure. The as-synthesized nanohelices were all double-stranded and left- and right-handed nanohelices were both formed. The helical nanostructure is a new morphology of inorganic-organic hybrid materials on the nanoscale level and the exact formation mechanism of these helices still needs further investigation.
基金the financial support from Mazandaran University of Medical Sciences,Iran
文摘This study reports the successful so nochemical synthesis of novel Fe3O4/SiO2/ZnO-Pr6O11(Fe/Si/Zn-Pr6O11) nanocomposites using fructose as a green capping agent.The influence of various parameters containing capping agent,power and time of ultrasound irradiation was investigated to reach optimum morphology and size conditions.The products obtained were characterized by transmission electron microscopy(TEM),UV/Vis diffuse reflectance spectroscopy(DRS),Fourier transform infrared spectra(FT-IR),vibration sample magnetometer(VSM),scanning electron microscopy(SEM),energy dispersive X-ray microanalysis(EDS) and X-ray diffraction(XRD).The Fe3O4/SiO2/ZnO-Pr6O11 nanocomposites display remarkably enhanced photocatalytic activity towards rhodamine b degradation(89.6%)and Congo red(84.7%) under UV irradiation compared with the other products.The results illustrate that the photocatalytic efficiency of magnetic nanocomposites is very much higher than pure Pr6O11nanostructures.Magnetic photocatalyst still has good stability after five successive runs.So,these recyclable nanocomposites can play a role in the treatment of both industrial and domestic contaminated water.
基金supported by Korea Basic Science Institute (National research Facilities and Equipment Center)grant funded by the Ministry of Education. (Nos.2019R1A6C1010042,2021R1A6C103A427)support from National Research Foundation of Korea (NRF), (Nos.2022R1A2C2010686,2022R1A4A3033528,2020R1I1A1A01065748,2021R1I1A1A01060380).
文摘Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H 2 fuel production.One of the sustainable and efficient techniques is electrocatalytic water split-ting for H 2 generation,but it is still restricted by the kinetically sluggish OER.Due to the lower standard oxidation potential of−0.33 V,replacing the OER with anodic hydrazine oxidation reaction(HzOR)is an effective way to extensively reduce the use of electricity in water electrolysis.Through alloying,the semiconductor and adsorption characteristics of Cu,interlaced by Pd 2+solution on the Pd surface by pulsed laser ablation(PLA)in methanol,are selectively altered to maximize cathodic HER and anodic HzOR performance.The optimal Cu1Pd3/C ratio demonstrates outstanding HER performance with a low overpotential of 0.315 V at 10 mA cm^(−2),as well as an ultralow overpotential of 0.560 V for HzOR in 0.5 M N_(2) H_(4)/1.0 M KOH.Furthermore,the constructed HzOR-assisted electrolyzer cell with Cu1Pd3/C||Cu1Pd3/C as anode and cathode exhibits a cell voltage of 0.505 V at 10 mA cm^(−2) with exceptional en-durance over 5 h.The current study advances competent CuPd alloys as multifunctional electrocatalysts for H 2 fuel production using a HzOR-assisted energy-efficient electrolyzer.
基金supported by VGST,Govt.of Karnataka,India(VGST/K-FIST-L1/2016-17/GRD-360)
文摘The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu^(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu^(3+):Li^+ in solid state display and photocatalytic applications.
