Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction ...Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV lamp.The results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal pattern.Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content.First,large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency.By contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal rate.The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.展开更多
In this research, synthesis of magnesium oxide-multi walled carbon nanotube （MgO/MWCNTs） nanocomposite is reported using sol-gel method in which magnesium nitrate is added to aqueous solution. The structure of MWCNT...In this research, synthesis of magnesium oxide-multi walled carbon nanotube （MgO/MWCNTs） nanocomposite is reported using sol-gel method in which magnesium nitrate is added to aqueous solution. The structure of MWCNTs and MgO/MWCNTs composite has been characterized by analyzing the X-ray diffraction pattern （XRD）, Fourier Transform Infrared （FT-IR） spectra and Scanning Electron Microscopy （SEM） images. Experimental results indicate that the surface of purified MWCNTs sample is covered homogenously by a layered of MgO nanoparticles.展开更多
In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In a...In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.展开更多
Synthesis of composite oxides in the series Nd4-xCs2（1＋x）Fe5-xZnxO14＋δ（0≤x≤1.0） （B1-B5： x= 0.0, 0.25, 0.5, 0.75, 1.0） is performed by sol-gel method via nitrate-acetate precursor route. Analysis of the pow...Synthesis of composite oxides in the series Nd4-xCs2（1＋x）Fe5-xZnxO14＋δ（0≤x≤1.0） （B1-B5： x= 0.0, 0.25, 0.5, 0.75, 1.0） is performed by sol-gel method via nitrate-acetate precursor route. Analysis of the powder x-ray diffraction （XRD） patterns show tetragonal unit cell with lattice parameters a = 8.6545, 8.2520, 7.7645, 9.8952, 8.2863 A; b = 8.9800, 11.5788, 15.6305, 8.4766, 11.6465 A in B1-B5, respectively. The average crystallite sizes in the samples are found to be in the range 69.56-119.48 A. Energy dispersive analysis of x-rays （EDAX） result shows the presence of Fe, Nd, Cs and O, and Fe, Nd, Zn, Cs and O in B 1 （x=0） and B2（x=0.25）-B5（x= 1.0）, respectively. The IR results at 300 K show the presence of octahedral [NdO6/2]^3- （asymmetric stretch： 410-416 cml） and [FeO6/2]^3-（symmetric stretch： 562-572 cm^-1） units in the samples. Observed magnetic moments versus magnetic field plots in the range -10 kG to ＋10 kG exhibit hysteresis loops with average magnetic susceptibility values in the range 3.46 × 10^-5 -7.05 × 10^-5 emu/gG in B1-B5 shows fairly strong ferromagnetic nature of the samples. The observed EPR lineshapes at 300 and 77 K with giso=2.01-2.03 and giso=2.01-2.03, respectively is ascribed to the octahedral [FeO6/2]^3- coordination of Fe^3＋ （3d^5） ion. The optical absorption spectra show the transition of ^4I9/2→^4F7/2→^ 4S3/2 （750 nm） of optically active Nd^3＋ ions in samples.展开更多
文摘Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV lamp.The results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal pattern.Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content.First,large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency.By contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal rate.The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.
文摘In this research, synthesis of magnesium oxide-multi walled carbon nanotube （MgO/MWCNTs） nanocomposite is reported using sol-gel method in which magnesium nitrate is added to aqueous solution. The structure of MWCNTs and MgO/MWCNTs composite has been characterized by analyzing the X-ray diffraction pattern （XRD）, Fourier Transform Infrared （FT-IR） spectra and Scanning Electron Microscopy （SEM） images. Experimental results indicate that the surface of purified MWCNTs sample is covered homogenously by a layered of MgO nanoparticles.
基金Fujian Province I mportant Science and Technology Development Fund,China (No.2005Z17)
文摘In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.
文摘Synthesis of composite oxides in the series Nd4-xCs2（1＋x）Fe5-xZnxO14＋δ（0≤x≤1.0） （B1-B5： x= 0.0, 0.25, 0.5, 0.75, 1.0） is performed by sol-gel method via nitrate-acetate precursor route. Analysis of the powder x-ray diffraction （XRD） patterns show tetragonal unit cell with lattice parameters a = 8.6545, 8.2520, 7.7645, 9.8952, 8.2863 A; b = 8.9800, 11.5788, 15.6305, 8.4766, 11.6465 A in B1-B5, respectively. The average crystallite sizes in the samples are found to be in the range 69.56-119.48 A. Energy dispersive analysis of x-rays （EDAX） result shows the presence of Fe, Nd, Cs and O, and Fe, Nd, Zn, Cs and O in B 1 （x=0） and B2（x=0.25）-B5（x= 1.0）, respectively. The IR results at 300 K show the presence of octahedral [NdO6/2]^3- （asymmetric stretch： 410-416 cml） and [FeO6/2]^3-（symmetric stretch： 562-572 cm^-1） units in the samples. Observed magnetic moments versus magnetic field plots in the range -10 kG to ＋10 kG exhibit hysteresis loops with average magnetic susceptibility values in the range 3.46 × 10^-5 -7.05 × 10^-5 emu/gG in B1-B5 shows fairly strong ferromagnetic nature of the samples. The observed EPR lineshapes at 300 and 77 K with giso=2.01-2.03 and giso=2.01-2.03, respectively is ascribed to the octahedral [FeO6/2]^3- coordination of Fe^3＋ （3d^5） ion. The optical absorption spectra show the transition of ^4I9/2→^4F7/2→^ 4S3/2 （750 nm） of optically active Nd^3＋ ions in samples.
