Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive a...Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive additive.The condensates were isolated by vacuum distillation under 5 kPa.The product was characterized by Fourier transform infrared(FT-IR) spectra,Raman spectra and nuclear magnetic resonance(NMR) spectra.The results indicate that the product is niobium ethoxide.Thermal properties of niobium ethoxide were analysed by TG/DTG.Vapour pressure was calculated from the Langmuir equation and the enthalpy of vaporization was calculated from the vapour pressure-temperature data using the Clausius-Clapeyron equation.The concentrations of impurity metallic elements in the sample were detected by ICP-MS.It is shown that the purity can reach 99.997%.The volatility and purity of the niobium ethoxide ensure that it could be a good precursor for chemical vapor deposition and atomic layer deposition of niobium oxide layers.展开更多
Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma...Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.展开更多
基金Project(2007AA03Z425) supported by the National Hi-tech Research and Development Program of ChinaProject(50404011) supported by the National Natural Science Foundation of China
文摘Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive additive.The condensates were isolated by vacuum distillation under 5 kPa.The product was characterized by Fourier transform infrared(FT-IR) spectra,Raman spectra and nuclear magnetic resonance(NMR) spectra.The results indicate that the product is niobium ethoxide.Thermal properties of niobium ethoxide were analysed by TG/DTG.Vapour pressure was calculated from the Langmuir equation and the enthalpy of vaporization was calculated from the vapour pressure-temperature data using the Clausius-Clapeyron equation.The concentrations of impurity metallic elements in the sample were detected by ICP-MS.It is shown that the purity can reach 99.997%.The volatility and purity of the niobium ethoxide ensure that it could be a good precursor for chemical vapor deposition and atomic layer deposition of niobium oxide layers.
基金Project(10JJ5057)supported by the Hunan Provincial Natural Science Foundation of China
文摘Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.
