溶剂化金属原子浸渍法制备Pd-Cu/γ-Al2O3低温CO氧化催化剂

Nano-particle Pd/γ-Al₂O₃ monometallic and Pd-Cu/γ-Al₂O₃ bimetallic catalysts were prepared by solvated metal atom impregnation (SMAI) method. The results of XRD measurement indicated that Pd- Cu alloy was formed in the bimetallic catalysts and the crystalline particle size of the alloy increased as Cu contents increased with av-erage diameters < 6.0nm for all the samples. XPS and Auger spectra showed that Pd was in zero- valent state, Cu existed mainly in zero- valent state and partially in monovalent state Cu⁺. The Pd/γ-Al₂O₃ and Pd-Cu/γ-Al₂O₃ catalysts exhibited higher activity for CO oxidation at low temperature. The activity of Pd-Cu/γ-Al₂O₃ bimetallic catalyst was higher than that of Pd/γ-Al₂O₃ monometallic catalyst. The Pd-Cu/γ-Al₂O₃ catalyst with Pd/Cu atomic ratio of 1∶1 showed the highest activity.     

水热改性对NiMo/γ-Al2O3加氢脱氮催化剂结构及性能的影响

The influence of hydrothermal modification on the structure and hydrodenitrogenation (HDN) activity of NiMo/γ-Al₂O₃catalyst was studied in the range 140～180 ℃. The experimental results indicated that the hydrodenitrogenation reaction rate of pyridine was accelerated using the NiMo/γ-Al₂O₃catalyst synthesized via hydrothermal route due to the change of the structure, the increase of the amount of Mo and Ni and the rise of the specific surface area. The change of the structure of catalysts was enhanced at higher hydrothermal temperature, producing NiMo/γ-Al₂O₃catalyst with better HDN activity.     

Ceramic Filter Balls Loaded with α-Fe2O3 and Their Application to NH3-N Wastewater Treatment

Hydrolysis reaction of Fe(NO₃)₃ at a high temperature in the presence of urea as the homogeneous precipitant was studied. With the prepared ceramic filter balls loaded with α-Fe₂O₃ after high temperature calcination, the loading of α-Fe₂O₃ on the porous ceramic filter balls from Fe(NO₃)₃ solutions of different concentrations and mechanical stability of the loaded α-Fe₂O₃ were studied. The product was characterized using XRD and SEM. Adsorption experiments were conducted to evaluate the performance of the product in adsorbing NH₃-N. It turned out that the specific surface area of the ceramic filter balls loaded with α-Fe₂O₃ had increased to 36.5387 m²/g from original 4.6127 m²/g. When the concentration of Fe(NO₃)₃ was 0.40 mol/L, the loading of α-Fe₂O₃ on the ceramic filter balls accounted for 8.4% of the total mass of the adsorbent and α-Fe₂O₃ was adsorbed on the filter balls very well. The adsorption isotherm of NH₃-N on the ceramic filter ball adsorbent loaded with α-Fe₂O₃ was of Langmuir type. The saturated adsorption capacity was 3.33 mg/L, and the adsorption constant K was 0.1873. NH₃-N was adsorbed by α-Fe₂O₃ more easily, which was a kind of specific adsorption.     

溶剂热合成具有纳米孔结构的γ -Al2O3

Nanoporous gamma aluminum oxide (γ-Al₂O₃) was synthesized by solvothermal method in the presence of AlCl₃·6H₂O, urea and alcohol. The calcined sample was characterized by XRD, FTIR, TEM, and Nitrogen adsorption-desorption measurement. Results show that the obtained γ-Al₂O₃ is well-dispersed nanoparticles with particle size of 4～7 nm and the product has nano-pore structure with a narrow pore size distribution of 5～20 nm.     

γ-Al2O3表面原位合成Ni-Al-CO3LDHs研究

Ni-Al-CO₃LDHs/γ-Al₂O₃have been prepared using an in-situ synthesis technique. NH₃·H₂O was chosen as activation agent of Al on the γ-Al₂O₃surface as well as precipitant. Ni-Al-CO₃LDHs/γ-Al₂O₃was synthesized by controlling the reaction conditions such as temperature, concentration of Ni²⁺ and initial pH. The crystalline structure, chemical composition and porous structure were characterized by means of XRD, FT-IR, TG-DTA, ²⁷Al MAS-NMR and N₂ adsorption-desorption. The resulting sample of Ni-Al-CO₃LDHs/γ-Al₂O₃possesses higher specific area and narrower pore distribution, in which Ni-Al-CO₃LDHs are located on the surface of γ-Al₂O₃and share the same Al-O bonds with the γ-Al₂O₃lattice. Finally a possible structural model was proposed to account for the porous characters of Ni-Al-CO₃LDHs/γ-Al₂O₃.     

SrCe0.95Er0.05O3-α固体电解质的导电性

SrCe_0.95Er_0.05O_3-α ceramic of a single orthorhombic phase of perovskite-type SrCeO₃ was prepared by high-temperature solid state reaction. Using the ceramic as solid electrolyte and porous platinum as electrodes, the measurements of conductivities and ionic transport numbers on SrCe_0.95Er_0.05O_3-α ceramic were performed by using electrochemical methods in the temperature range of 600～1 000 ℃ in wet hydrogen, dry air and wet air, respectively. The results indicate that the sample is a pure protonic conductor with a maximal conductivity of 0.01 S·cm^-1 in wet hydrogen, a mixed conductor of oxide-ion and hole in dry air, and a mixed conductor of proton, oxide-ion and hole in wet air.     

微量吸附量热研究CuO/γ-Al2O3催化剂的表面酸碱性质

The γ-Al₂O₃ supported CuO samples were studied. XRD results showed that the loading and calcination temperature affected the surface structure. For example， CuO crystallite appeared at the CuO loading of 7% (about 0.82mmol/100m²) on the support. Both CuO crystallite and CuAl₂O₄ spinel were present when the CuO/γ-Al₂O₃ sample was calcined at the same temperature (400℃). Microcalorimetric adsorption of CO₂ and NH₃ revealed that the strength of both the acidity and basicity decreased with the increase of CuO loading for the CuO/γ-Al₂O₃ sample. The increase of calcination temperature further decreased the basicity while the acidity was not affected.     

Nd2O3添加量对BaTiO3陶瓷介电性能的影响

BaTiO₃ ceramics doped with Nd₂O₃(the additive content was respectively 0.001,0.002,0.003,0.005,0.01,0.03mol)were prepared by Sol-Gel method. Effects of Nd₂O₃ contents on the dielectric constant (ε), the dielectric loss (tanδ) ,the Curie-temperature (T_C) and the resistivity (ρ) of BaTiO₃ ceramic were studied. When Nd₂O₃ content was 0.001mol and 0.002mol, the dielectric constant was increased obviously, but the dielectric loss was also increased. When Nd₂O₃ content was 0.003mol, the dielectric constant was increased, and the dielectric loss was decreased, which was suitable for application in condenser. The resistivity was decreased obviously with the increasing of Nd₂O₃ contents, the resistivity was the smallest when Nd₂O₃ content was 0.001mol. The Curie-temperature was also decreased with the increasing of Nd₂O₃ contents.     

纳米空腔堆积的一维碳纳米结构的合成与表征

Quasi-periodically intermittent hollow-cavity-stacked one-dimensional carbon nanostructures were obtained by microwave plasma chemical vapor deposition from the mixture of CH₄ and N₂ on Fe/γ-Al₂O₃ catalyst. This structure was characterized by transmission electron microscope (TEM), high-resolution TEM and X-ray energy dispersive spectral analysis. The results indicate that the trace impurity of nitrogen might account mainly for the formation of these novel nanostructures. The structural units in these one-dimensional carbon nanostructures are full of nanocavities, which may be of potential importance in hydrogen storage.     

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 ℃.