电化学沉积技术制备LiNiO2薄膜及表征

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.     

通过β-FeOOH纳米棒无序聚集制备α-Fe2O3中空球

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.     

CeOHCO3和CeO2束状纳米结构的制备及表征

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.     

电镀烧结法制备Ti/SnO2-Sb2O4电极的研究

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.     

MgCl2晶型对丙烯聚合MgCl2载体催化剂活性的影响

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.     

湿法水解制备可见光催化剂N/TiO2

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.     

反相微乳液法合成SrTiO3纳米棒

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 ω₀ [ω₀=n_H2O/ n_CTAB], 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.     

纳米Co3O4的制备、 表征及CO低温催化氧化

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.     

电沉积HA/TiO2复合涂层的结合强度和热稳定性研究

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 ℃.     

纳米PbSnO3的制备及其燃烧催化性能的研究

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%）.     

锐钛矿型TiO2水溶胶的低温制备及其表征

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.     

微波辐照方式对CdS和Bi2S3纳米粒子结晶度的影响

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.     

磷酸盐直接共沉淀法制备K0.6Sr0.7Zr4P6O24纳米粉末

Nanometer K_0.6Sr_0.7Zr₄P₆O₂₄ (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.     

不同稀土改性SO42-/ZrO2催化剂的结构与性能表征

Solid superacid catalyst SO₄^2-/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 SO₄^2- efficiently. The optimum calcination temperature and molar ratio of Ce(NH)∶Zr for SO₄^2-/ZrO₂ catalyst modified by (NH₄)₂Ce(NO₃)₆ are 450 ℃ and 2, respectively.     

有机体系中纳米TiO2 / ZrO2修饰电极的制备及电催化活性

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.     

共沉淀法制备负热膨胀性ZrW2O8粉体及其粒径控制初探

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.     

钛酸锌的制备及其对高氯酸铵热分解的催化性能

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.     

PdCl2/ O-MCM-41催化剂制备及其在苯酚氧化羰化反应中的应用

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).     

TiO2 / SiO2核 / 壳结构复合粒子的组装及其电化学性能

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.     

准球形α-Fe2O3的形成过程研究

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.