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1.
赖欣  毕剑  史芳  高道江  肖定全 《无机化学学报》2006,22(10):1929-1932
Well-crystallized LiNiO2 thin films were prepared directly on nickel substrates in LiOH solution by constant current electrochemical deposition technique at 95 ℃. The as-prepared LiNiO2 thin films were characterized by using XRD, SEM and XPS, and the results reveal that the as-prepared LiNiO2 thin films are dense and uniform in surface and show hexagonal structure. The influence of processing parameters such as reaction temperature, duration, electrical current density as well as the concentration of LiOH solution on the structure and morphologies of as-prepared LiNiO2 thin films were studied,and the preferable electrochemical processing conditions for preparing LiNiO2 thin films were suggested.  相似文献   

2.
The α-Fe2O3 hollow spheres have been synthesized through the random aggregation of β-FeOOH nanorods in the C2H5OH/H2O system. The phase transformation and the morphologies of the α-Fe2O3 hollow structure were investigated with XRD, SEM, TEM and selected area electron diffraction (SAED). These studies indicate that the second step is a dissolution-recrystallization process. Furthermore, the formation mechanism of the hollow spheres has been discussed. It is found that the presence of H2O in the reaction system is essential to the final formation of the hollow spheres.  相似文献   

3.
The cantaloupe-like particles of CeOHCO3 were synthesized in aqueous solution by using cetyltrimethylammonium bromide (CTAB) as soft template. Then, the bunchiness rods of CeO2 were obtained by calcining CeOHCO3 at 450 ℃. The results of thermogravimetric/differential thermal analysis reveal that an endothermic reaction with decomposition is involved in the transformation process from CeOHCO3 to CeO2. By scanning electron microscopy and X-ray diffraction analysis, it is found that the orthorhombic phase CeOHCO3 particles are constituted of short nanorods with diameters ranging from several tens nm to over 100 nm, and the cubic phase CeO2 rods are composed of small particles with diameter ca. 15 nm. From the results of UV-Vis absorption and photoluminescence analysis, it is found that the CeO2 possess abundant defects, and the band gaps of the CeO2 and CeOHCO3 are ca. 2.70 eV and 3.87 eV, respectively.  相似文献   

4.
电镀烧结法制备Ti/SnO2-Sb2O4电极的研究   总被引:1,自引:0,他引:1  
张乃东  李宁  彭永臻 《无机化学学报》2002,18(11):1173-1176
The Ti/SnO2-Sb2O4 electrode has been prepared by the electroplate-sinter method. The effect of SbCl3 adding amount and sintering temperature on its electrode lifetime and oxygen evolution potential were investigated by means of EDX, SEM and XRD analysis. The results indicated that the electrode appeared the best performance when the SbCl3 adding amounts was 0.2g and the sintering temperature was 550℃. In optimized conditions Ti substrate was entirely covered by SnO2-Sb2O4 and the combinations among them were tight. Due to the use of electroplate method, the electrical conductivity, the oxygen evolution potential and the electrode lifetime were increased, so the elec-tro-catalytic activity and the electrochemical stability of the prepared electrode were found to be superior.  相似文献   

5.
The influence of MgCl2 crystal modification (α- MgCl2, β- MgCl2 ) on theproperties of supported catalyst for propylene polymerization has been studied bymeans of XRPD, IR and DTA-TG. The structural difference and similarity between α- MgCl2 and β- MgCl2 was still reclined in its milling produCt withdiisobutyl phthalate and in the catalysts prepared from α- MgCl, and β-MgCl2caaccers respectively. β-MgCl2 supported catslyst gives higher activity and lowerstcreospedficity than α- MgCl2. The catalyst prepared by using Mg(OEt)2 as carrier shows higher activity and stereospecificity than both a-MgCl2 and β-MgCl2 sup-ported catalysts.  相似文献   

6.
SrTiO3 nanorods were synthesized in cetanyl trimethyl ammonium bromide (CTAB) reverse microemulsion containing CTAB, n-hexanol, n-octane and water with Ba(OH)2 as reactants. The effects of different conditions such as ω00=nH2O/ nCTAB], aging time and the concentration of reactants on the formation of the nanorods were studied. Transmission electron microscope (TEM), electron diffraction (ED) and X-ray diffraction(XRD)were used to characterize the morphology and the structure of the synthesized nanorods. The results show that SrTiO3 nanorods with a length of 260~2 000 nm and a diameter of 50~100 nm belonging to single crystal are single cubic system. The molar ratio of Sr to Ti of products is 1.0 as determinded by ICP.  相似文献   

7.
湿法水解制备可见光催化剂N/TiO2   总被引:3,自引:0,他引:3       下载免费PDF全文
The N/TiO2 was prepared by wet hydrolyzation method. The photocatalytic decomposition of benzoic acid solution was carried out under simulated sun light; the photocatalytic activity was 2.47 times of TiO2. The products were characterized by XRD, SPS, EFISPS and XPS, respectively. The results of XRD showed that the N could restrain the crystallization transformation of TiO2 from anatase to rutile. The N/TiO2 was still n-type semiconductor, and the absorbance wavelength appeared red-shifted by N-doping. The band gap of N/TiO2 was decreased to 2.7 eV. The amount of doped-N is about 0.94at.%. The binding energy of N1s are 396.62 eV (Ti-N bonds, β-N) and 400.87 eV (N-N bonds, γ-N2), respectively, and the photocatalytic activity of N/TiO2 under visible light is related to the β-N. The N atoms replace the O of the TiO2 and form the Ti-N bonding.  相似文献   

8.
纳米Co3O4的制备、 表征及CO低温催化氧化   总被引:1,自引:0,他引:1  
Various nanometer Co3O4 samples were prepared and the catalytic performance of CO oxidation were examined. It was found that the activities of the catalysts were greatly changed with variation of the preparation methods and pretreatment conditions. Among the samples tested, Co3O4 prepared by using dodecylbenzene sulfonic acid sodium salt(DBS) as the surfactant, calcined at 300 ℃ showed the highest activity and it was able to oxidize completely CO even at -78 ℃. Characterization of these samples by XRD and BET means showed that the catalytic acitivity increased with the decrease of the average particle size, suggests that the average particle size of nanometer Co3O4 samples is the main controlling factor of the catalytic activity.  相似文献   

9.
电沉积HA/TiO2复合涂层的结合强度和热稳定性研究   总被引:6,自引:0,他引:6  
HA/TiO2 composite coating were fabricated via adding TiO2 powder in the electrolyte by electrodeposition. The influence of current density and deposition time on the content of TiO2 in the coating, the influence of the content of TiO2 in the coating on the bonding strength of coating and the influence of sintering temperature on the structure and the bonding strength of coating were investigated. The experiment results show that the content of TiO2 in the coating increase with reducing the current density and prolonging the deposition time, the bonding strength improve with increasing the content of TiO2 in the coating, which can obtain 18.7 MPa when the weight percent TiO2 in the coating attain 72.2 %. The addition of TiO2 in the coating reduces the thermal expansion coefficient of the coating, improves the bonding strength of coating and changes the fracture mechanism of the coating from adhesion failure to cohesive failure. HA in the composite coatings is decomposed by the catalysis reaction of TiO2 at the temperature of sinter 850 ℃. Differential scanning calorimetry and X-ray diffractometry analyses showed that the chemical reaction between HA and TiO2 lead to the product are α-TCP and CaTiO3 at the temperature of sinter 1200 ℃. In order to prevent the coating from decomposing and attain hign bonding strength, the sintering temperature should be less than 820 ℃.  相似文献   

10.
纳米PbSnO3的制备及其燃烧催化性能的研究   总被引:1,自引:0,他引:1  
Nanocomposite PbSnO3was synthesized by coprecipitation method , and its phase evolution process was investigated. The particle size, crystal form, and phase of samples were determined with XRD, TEM and EDS. The catalytic actiyity of sample on the thermal decomposition of RDX was investigated by DSC. The results show that nanocomposite PbSnO3with the diameter of 9 nm can be obtained by calcining at 600 ℃ for 2 h, which crystal is cubic (pyrochlore type). The catalytic actiyity of nanocomposite PbSnO3on the thermal decomposition of RDX is much higher than that of normal PbSnO3. The nanocomposite PbSnO3can decrease the peak temperature of thermal decomposition of RDX from 240.1 ℃ to 236.5 ℃, and the decomposition enthalpy ΔH of RDX increases 722 J·g-1 (about 70%).  相似文献   

11.
微波辐照方式对CdS和Bi2S3纳米粒子结晶度的影响   总被引:4,自引:0,他引:4       下载免费PDF全文
The effect of traveling microwave irradiation on the crystallinities of CdS nanoparticles and Bi2S3 nanorods was studied. Results showed that as compared with stationary microwave irradiation the crystallinities and the crystal growth of sulfide nanoparticles were improved. Traveling microwave irradiation can supply narrower frequency distribution and stronger power density of irradiation, CdS nanoparticles and Bi2S3 nanorods obtained are better in crystallinities and larger in size than under stationary microwave irradiation.  相似文献   

12.
锐钛矿型TiO2水溶胶的低温制备及其表征   总被引:7,自引:0,他引:7  
Anatase titanium dioxide hydrosol was prepared at low temperature by a simple method. The title material was characterized by TEM, XRD, FTIR and BET, respectively. The photocatalytic activity of the as-prepared TiO2 was evaluated by the degradation of methyl orange solution under sunlight and the photocatalytic oxidation of acetone in air. The results showed that the titanium dioxide hydrosol was composed of anatase phase with average grain size of about 7 nm, and the crystallinity became more perfect with the increase of temperature. The BET surface areas were more than 220 m2·g-1 for these samples. It is found that the photocatalytic activity was much better for the higher heat processing temperature. Especially, the photocatalytic activity of the sample with a heat treatment of 110 ℃ was better than that of P25. In addition, TiO2 hydrosol also possessed good photocatalytic activity under the sunlight illumination.  相似文献   

13.
磷酸盐直接共沉淀法制备K0.6Sr0.7Zr4P6O24纳米粉末   总被引:3,自引:0,他引:3  
Nanometer K0.6Sr0.7Zr4P6O24 (KSZP)powders were synthesized from KNO3, Sr(NO3)2, NH4H2PO4 and ZrOCl2·8H2O by direct co-precipitation method. The as-prepared precipitates and KSZP powders were characterized by thermal analysis, XRD, particle-size analyzer and SEM measurements. The results showed that the precipitates could be heat-treated at near 580 ℃ and 900 ℃, and the crystallization of the KSZP powder product depends on treatment temperature. It was non-crystalline after dried at 80 ℃, became incomplete crystalline KSZP after heat-treated at 900 ℃ and was single-phase KSZP after calcined at 1 380 ℃. The mean particle size and particle-size distribution of KSZP powder after heat-treated at 900 ℃ were smaller and narrower than those after dried at 80 ℃ and calcined at 1 380 ℃, and were 62 nm and 40~100 nm, respectively. The particle shape of the powder after heat-treatment was spheric, and the reuniting or agglomeration was found. Phosphate direct co-precipitation was more suitable than phosphate converse co-precipitation to synthesize nanometer single-phase KSZP powder and the sintered body with the nanometer powder possesses better integral sintering properties.  相似文献   

14.
不同稀土改性SO42-/ZrO2催化剂的结构与性能表征   总被引:3,自引:0,他引:3  
Solid superacid catalyst SO42-/ZrO2 was modified by different rare earth compounds and applied to the esterification of acetic acid and n-butanol. The effects of rare earth elements loading on the catalytic properties were studied and the correlation between the structure and properties was investigated by means of XRD, IR, UV, DTA and TG. The results show that the (NH4)2Ce(NO3)6 modification can enhance catalytic activity more and exhibit better stability than the other two compounds La(NO3)3 and Ce(NO3)3. Meanwhile,(NH4)2Ce(NO3)6 modification can restrain the loss of SO42- efficiently. The optimum calcination temperature and molar ratio of Ce(NH)∶Zr for SO42-/ZrO2 catalyst modified by (NH4)2Ce(NO3)6 are 450 ℃ and 2, respectively.  相似文献   

15.
The complexes Ti(OCH2CH2O)2 and Zr(OCH2CH2O)2 were directly synthesized by using HOCH2CH2OH dissolution in 50 mL flask. The nano-ZrO2 / TiO2 powders were prepared by a direct sol-gel synthesis using the above solution and followed by drying at 400 ℃ for 2 h. The complexes were characterized by FTIR and 1H NMR. XRD and TEM were used to investigate the structure of nano-ZrO2 / TiO2. The results show that the complexes containing -OCH2CH2O- group could prevent the precursor from agglomeration and sintering during the hydrolysis and calcination process. The ZrO2 / TiO2 powders of 20~35 nm was thus obtained in a high purity. The highly active nano-ZrO2 / TiO2 modified electrode was prepared by using daubing and calcination. The electro-catalytic activities of this electrode in (COOH)2 were investigated. The discharge current of nano-ZrO2 / TiO2 electrode increased obviously. In preparative electrolysis under optimal conditions, the average yield and current efficiency for HOOC-CHO were 84.7% and 91.6 %, respectively.  相似文献   

16.
共沉淀法制备负热膨胀性ZrW2O8粉体及其粒径控制初探   总被引:6,自引:0,他引:6  
Negative thermal expansion (NTE) material ZrW2O8 powders were synthesized using co-precipitation route. The precursor of ZrW2O8 was studied by Thermogravimetric and differential scanning calorimetry (TG-DSC). The structure and morphology of the resulting powders were characterized by Powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM), respectively. The results showed that the samples were single phase of α-ZrW2O8 with regular shape. High temperature X-ray diffraction measurement indicated that the thermal expansion coefficient of ZrW2O8 was -10.35 × 10-6 K-1 in the temperature range from room temperature to 150 ℃, -3.08 ×10-6 K-1 from 200 ℃ to 600 ℃ and the average value was -5.38 × 10-6 K-1. At the same time, polyethylene glycol (PEG) was used as dispersant to primary control the size of ZrW2O8.  相似文献   

17.
ZnTiO3 nanocrystals were prepared by sol-gel method, using Zn(NO3)2 and Ti(C4H9O)4 in the topic. The as-prepared ZnTiO3 nanocrystals were characterized by XRD, FTIR and TEM, and the catalytic performance of ZnTiO3 nanocrystals of different contents for the ammonium perchlorate(AP)decomposition was investigated by thermal analysis. The results indicate that ZnTiO3 with pure cube structure can be synthesized at 600 ℃ by this procedure,which was spheroid with particle size of about 60~100 nm. The results expressed that the low temperature decomposition peaks of AP is advanced by 17 ℃ and the high temperature decomposition peaks of AP is advanced by 24 ℃ when adding 5% nanoparticle ZnTiO3 powder. The catalytic effects of ZnTiO3 powders on the high temperature decomposition of AP are less than that of nanometer metal powders, but all the micron metal powders decrease the low decomposition temperature of AP.  相似文献   

18.
TiO2 coated SiO2 materials as anode for lithium-ion batteries were synthesized via an in situ hydrolysis of tetraethyl orthosilicate under ultrasonic irradiation using nanometer-sized TiO2 colloids as precursors. The XRD patterns indicate that the as-prepared core/shell particles remain anatase after calcining below 800 ℃. TEM observation shows that the particle size of TiO2 / SiO2 composites is ca. 200 nm, and a homogeneous SiO2 layer is coated on the surfaces of TiO2 particles. FTIR spectra demonstrate that SiO2 could have been coated on the surfaces of TiO2 particles via a chemical bonding. In addition, the first specific charge and discharge capacities of the coated particle electrode were 66.4 mAh·g-1 and 90.7 mAh·g-1, respectively, which indicates that the TiO2 / SiO2 particles are more stable than the monodispersed TiO2. Meanwhile, the new material has good lithium intercalation-deintercalation performances.  相似文献   

19.
PdCl2/ O-MCM-41催化剂制备及其在苯酚氧化羰化反应中的应用   总被引:1,自引:0,他引:1  
Hybrid mesoporous silica MCM-41 (O-MCM-41) was prepared using γ-aminopropyltriethoxysilane (APTES) as spacer, tetraethoxysilane as precursor and 2-acetylpyridine as organic moiety. The heterogeneous palladium catalyst (PdCl2/ O-MCM-41) was then prepared by reaction of the hybrid MCM-41 with PdCl2(PhCN)2. The products were characterized by means of IR, XRD, XPS and N2 adsorption-desorption isotherms. The catalytic properties of the supported catalyst in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) were investigated. The yield of DPC and turnover number (TON) reached 5.8% and 29 mol DPC·mol Pd-1, and Pd loss was only 2.7% at 110 ℃, 4.4 MPa for catalytic reaction of 5 h with 4.2wt% Pd loading, and molar ratio of phenol to Pd being 1000 in the presence of Cu2O and terahydrofuran (THF).  相似文献   

20.
张霞  赵岩  张彩碚  李春文 《无机化学学报》2006,22(11):2113-2117
The formation process of pseudo-spherical α-Fe2O3 particles obtained through the hydrolysis of 0.01 mol·L-1 FeCl3 solution was studied by means of TEM and XRD. The results show that the growth of α-Fe2O3 nuclies is through the diffusion mechanism. Although the presence of CTAB in the FeCl3 solution has no effect on the growth process of pseudo-spheric α-Fe2O3 particles, more uniform particles are obtained, and the particles are self-assembled to form two-dimensional ordered structure due to the effect of CTAB. The optical character of these α-Fe2O3 particles was investigated, and the band-gap of which is about 2.49 eV.  相似文献   

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