合成大比表面γ-Mo2N的新方法

The production of high specific surface area γ-Mo₂N (up to 165 m²·g^-1, passivated) by temperature programmed reaction of MoO₃ with mixtures of N₂ and H₂ was reported. The synthetic condition of high surface area γ-Mo₂N (usually, S_BET>100 m²·g^-1) were quite difficult and the amount of starting material MoO₃ in each batch was much less than 0.5 gram. However, some synthetic conditions had been greatly improved in our experiments. The crystalline phase and specific surface area had been characterized by XRD and BET. The XRD gave some information for reaction mechanism.     

纳米晶SnO2粉体的合成

Crystalline tin oxide nanoparticles were synthesized by the direct precipitation from the starting material granulated tin. TG-DTA of the precursor showed a heavy weight loss at about 130℃ accompanied by an endothermic peak， two exothermic peaks above 200℃ accompanied by small weight loss indicated the decomposition and the oxidation of residual NO₃^- ion and PEG. XRD showed that obtained particles agreed well with the determination result of bulk SnO₂. The broadened XRD patterns became sharper as the calcining temperature turned to higher， it was indicated that the growth of the particle was exhibited. The surface area of the particles calcined at 300℃ was 161.1m²·g^-1 and declined as the calcining temperature turned to higher. TEM showed an heavier agglomeration at higher temperature.     

预氧化固气法合成LiNiO2的研究

LiNiO₂ was prepared by reaction of stoichiometric amounts of thoroughly-mixed LiOH·H₂O and preoxidation nanometer-scale Ni₃O₂(OH)₄ powders in O₂ at the temperature of 700℃ for 6h. The products were tested by XRD， XPS， SEM and electrochemistry methods. It was shown that product was LiNiO₂ single-phase， and the valence of nickel was +3; the average size of it was 40nm; its initial charge specific capacity is 168mAh·g^-1 and the coulomb efficiency is 90%; the second charge specific capacity is 160mAh·g^-1 and the coulomb efficiency is 96%.     

Cr/CeO2体系及其对乙烷脱氢反应催化性能的研究

The dehydrogenation reaction of ethane over Cr/CeO₂ catalysts in presence of CO₂ was studied with fixed-bed micro-reactor. The Cr/CeO₂ catalysts of different Cr loading have been synthesized using impregnation techniques. The Cr/CeO₂ system has already been found to be active and selective in the reaction at around 740 ℃. The function of carbon dioxide is to remove coke and hydrogen to accelerate dehydrogenation of ethane. The results of catalysts characterizations indicated that Cr³⁺ and Cr⁶⁺ occurred on the surface of the catalysts. The 1.2 mmol Cr/100m₂ CeO₂ catalyst sample with a monolayer dispersion of Cr on CeO₂ support showed a stronger surface acidity and a maximum yield of ethylene of about 35.5% at 36.6% conversion of ethane.     

预氧化对石油焦物理活化的作用

Activated carbon was prepared from pretreated petroleum coke by the vapor activation. The effect of pretreatment process on activation performance of coke was studied by low temperature N₂ adsorbtion-desorption and XRD. The results show that when the temperature is increased, coke loses volatiles with obvious volume contraction, resulting in decline in coke activation performance, the activated carbon obtained from carbonization coke after treatment at 650 ℃ is with a higher degree of graphitization, while pores below 1.5nm are disappeared. The oxidation pretreatment would modify the micro-structure of the coke and make the graphitization degree of coke decline. The activation performance of coke is improved greatly by air-oxidation pretreatment due to the formation of a mass of pore in coke with specific surface area about 146 m²·g^-1, and the surface area of activated carbon is considerably increased. The specific surface area of the activated carbon from air-oxidated coke reached 499m²·g^-1. Nitric acid pretreatment also had effect on improving activating performance of the petroleum coke.     

CuO/Sn0.8Ti0.2O2催化剂的表征及对NO+CO反应活性研究

Reducibility and characteristics of CuO/Sn_0.8Ti_0.2O₂ catalysts were examined by using a microreactor-GC NO+CO reaction system, BET, TG-DTA, FTIR, XRD and H2-TPR techniques. CuO/Sn_0.8Ti_0.2O₂ had high activity in NO+CO reaction, showing 93% NO conversion at 300 ℃ in air, and 100% NO conversion at 225 ℃ after H₂ pretreatment. The pore size distribution of Sn_0.8Ti_0.2O₂ was mainly as micro-pores and meso-pores (1~5 nm), and the specific surface area and total pore volume of Sn_0.8Ti_0.2O₂ were 69 m²·g^-1 and 0.15 cm³·g^-1, respectively. As shown by XRD analysis, there was no CuO crystal diffraction peak at 9%CuO loading, but two CuO crystal diffraction peaks at 2θ 35.5° and 38.7° were present at 12% CuO loading. FTIR detected the adsorption of NO and CO on the surface of reduced 12%CuO/Sn_0.8Ti_0.2O₂. The Cu²⁺ sites and support surface adsorbed NO, and the process of NO adsorption led to the formation of N₂O and NO₃^-. In contrast, the Cu⁺、Cu⁰ sites and support surface adsorbed CO, and when the mixed gases of NO and CO were adsorbed by support surface, no NO₃^- was formed. H₂-TPR showed four reduction peaks (α, β, γ and δ). The α, β and γ peaks were the reductions of CuO species, and the δ peak was the reduction of Sn_0.8Ti_0.2O₂.     

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.     

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.     

纳米固体超酸SO42-/TiO2的研究

The new nanosolid superacid catalyst SO₄^2-/TiO₂ is compounded with nanometer chemical technology. This catalyst SO₄^2-/TiO₂ has good catalytic effects on esterificational reactions of ethylic acid and ethyl alcohol. It has many other advantages such as strong water-proof quality, being able to be used repeatedly, being easy to be re-claimed, non-corroding, non-polluting. So it is a green industrial catalyst which is helpful to the environment and possesses wide prospect of applications. The crystallo-process, specific surface area and sulphur content of the SO₄^2-/TiO₂ system have been studied with the method of XRD, XPS and the chemical analysis, the result of which indicates that catalytic activity and acid strength of SO₄^2-/TiO₂ is affected by the H₂SO₄ saturant concentration, baking temperature, precipitating condition, specific surface area and sulphur content. The best preparation conditions of SO₄^2-/TiO₂ are: ageing temperature at 0℃, 0.5mol·L^-1 of H₂SO₄ concentration, baking temperature at 500℃and 3 hours of baking time.     

新型纳米多孔SiO2气凝胶微球材料的制备

A new type of nanoporous SiO₂ aerogel microsphere materials were synthesized by using SiO₂ sols as raw materials in the W/O emulsion formed by the emulsification of Tween-85 and Span-80. The obtained wet gel microspheres were aged by a successive solvent exchanging of alcohol, tetraethylorthosilicate (TEOS)/ethanol solution and ethanol at 60 ℃, and then were dried at ambient pressure to produce SiO₂ aerogel microspheres. The resultant SiO₂ aerogel microspheres were characterized by SEM, TEM and nitrogen adsorption-desorption. The results show that the prepared SiO₂ aerogel microspheres are nanoporous materials with coherent network nanoporous structure consisting of SiO₂ nanoparticles with an average diameter of about 10 nm. The apparent density of a typical sample is 0.4 g·cm^-3, while the specific surface area is 386 m²·g^-1, and the average pore size is 18 nm with the porosity of 84%. Various SiO₂ aerogel microspheres with the apparent particle sizes of 10～200 μm can be synthesized by controlling the stirring speed at 600～2 000 r·min^-1, the volume ratio of water/oil from 0.10 to 0.30, and the weight ratio of Tween-85/Span-80 less than 0.40.     

KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems

phase diagrams of KCl-KBO₂-K₂CO₃, K₂MoO₄-KBO₂-K₂CO₃, and K₂WO₄-KBO₂-K₂CO₃ ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E ₁: 622°C, 8.5 mol % KBO₂, 56.5 mol % KCl, and 35 mol % K₂CO₃; E ₂: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂MoO₄; E ₃: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂WO₄. The specific heats of melting of the eutectics were determined.     

Solubility in the Na2Cr2O7-(NH4)2Cr2O7-K2Cr2O7-H2O system

Solubility in the Na₂Cr₂O₇-(NH₄)₂Cr₂O₇-K₂Cr₂O₇-H₂O four-component water-salt system at 25, 50, and 75°C was studied for the first time. Phase field boundaries for individual salts and potassium and ammonium dichromate solid solutions, monovariant lines, and invariant points were determined. Experimental data were used to optimize the looped isohydric process of potassium dichromate preparation involving additional salts.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Li2SO4-Na2SO4-H2O和Li2SO4- K2SO4-H2O溶液的体积性质

本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li₂SO₄ + Na₂SO₄ + H₂O和 Li₂SO₄ + K₂SO₄ + H₂O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg_–1,混合溶液中Na₂SO₄和K₂SO₄的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θ_V和 ψ_V,模型的计算值与实验值的偏差在±0.002 g.cm_–3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。     

The preparation of NbH5(Me2PCH2CH2Me2)2 and NbHL2(Me2PCH2CH2PMe2)2 (L = CO or C2H4)

MMe₅(dmpe) (M = Nb or Ta, dmpe = Me₂PCH₂CH₂PMe₂) reacts with H₂ (500 atm) and dmpe in THF at 60°C to give MH₅(dmpe)_2? NbH₅(dmpe)₂ readily reacts with two mol of CO or ethylene (L) to give NbHL₂(dmpe)₂. The exchange of the hydride ligand with the ethylene protons in NbH(C₂H₄)₂(dmpe)₂ is not rapid on the ¹H NMR time scale (60 MHz) at 95°C.     

(H2NC4H8NCH2CH2NH2)(HNCH2CH2NH2)3Zn2Ge2Se8: A new,templated one-dimensional ternary semiconductor stabilized by mixed organic cations

The novel, 1D semiconductor (H₂NC₄H₈NCH₂CH₂NH₂)(HNCH₂CH₂NH₂)₃Zn₂Ge₂Se₈ has been synthesized under solvothermal conditions using N-(2-aminoethyl)piperazine as solvent and templating agent at 200 °C. The material was characterized by single crystal and powder X-ray diffraction, IR and Raman spectroscopy and thermogravimetric analysis. The compound consists of 1D anionic [Zn₂Ge₂Se₈]⁴⁻ chains made of alternating edge-shared [ZnSe₄] and [GeSe₄] tetrahedra that charged balanced by one N-(2-aminoethyl)piperazinium and three piperazinium cations. The optical properties were investigated with solid state UV–Vis/near IR spectroscopy and the results show that the solid is a medium gap semiconductor with an absorption edge at 1.8 eV.     

NaBO2-NaCl-Na2CO3, NaBO2- Na2CO3-NaMoO4, NaBO2- Na2CO3-NaWO4, and NaBO2-NaCl-Na2WO4 ternary systems

The phase diagrams of the NaBO₂-NaCl-Na₂CO₃, NaBO₂-Na₂CO₃-Na₂MoO₄, NaBO₂- Na₂CO₃-Na₂WO₄, and NaBO₂-NaCl-Na₂WO₄ ternary systems were studied by a calculation-experimental method and differential thermal analysis. The coordinates of ternary eutectics were determined: E ₁: 612°C, 16 mol % NaBO₂, 42 mol % NaCl, and 42 mol % Na₂CO₃; E ₂: 568°C, 12 mol % NaBO₂, 28 mol % Na₂CO₃, and 60 mol % Na₂MoO₄; E ₃: 575°C, 12 mol % NaBO₂, 32 mol % Na₂CO₃, and 56 mol % Na₂WO₄; E ₄: 628°C, 8 mol % NaBO₂, 20 mol % NaCl, and 72 mol % Na₂WO₄; and E ₅: 655°C, 9 mol % NaBO₂, 53 mol % NaCl, and 38 mol % Na₂WO₄.     

Synthesis and characterization of inorganic solid electrolytes of Li2O-SiO2-P2O5 and Li2O-TiO2-SiO2-P2O5 systems

The lithium-ion-conducting inorganic solid electrolytes in the oxide systems Li₂O-SiO₂-P₂O₅ and Li₂O-TiO₂-SiO₂-P₂O₅ were prepared by the solid-state reaction, and the electrolyte pellet made by cold-pressing method had diameter of 13 mm and was about 1 mm thick. Phase identification and surface morphology of the products were carried out by X-ray diffraction and scanning electron microscopy. Ionic conductivity of the pellets was investigated through ac impedance. The results show that the adding of other cations can improve the ionic conductivity of the solid electrolyte, and the sintering temperature and duration can influence the ionic conductivity. The maximum ionic conductivity in the samples is 9.9 × 10⁻⁴ S/cm in the Li₂O-TiO₂-SiO₂-P₂O₅ system. Original Russian Text ? W. Li, M. Wang, Z.H. Li, X.F. Shang, H. Wang, Y.W. Wang, Y.B. Xu, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 11, pp. 1341–1345.     

Polymorphism in the Sc2Si2O7-Y2Si2O7 system

This paper examines the structural changes with temperature and composition in the Sc₂Si₂O₇-Y₂Si₂O₇ system; members of this system are expected to form in the intergranular region of Si₃N₄ and SiC structural ceramics when sintered with the aid of Y₂O₃ and Sc₂O₃ mixtures. A set of different compositions have been synthesized using the sol-gel method to obtain a xerogel, which has been calcined at temperatures between 1300 and 1750 °C during different times. The temperature-composition diagram of the system, obtained from powder XRD data, is dominated by the β-RE₂Si₂O₇ polymorph, with γ-RE₂Si₂O₇ and δ-RE₂Si₂O₇ showing very reduced stability fields. Isotherms at 1300 and 1600 °C have been analysed in detail to evaluate the solid solubility of the components. Although, the XRD data show a complete solid solubility of β-Sc₂Si₂O₇ in β-Y₂Si₂O₇ at 1300 °C, the ²⁹Si MAS-NMR spectra indicate a local structural change at x ca. 1.15 (Sc_2−xY_xSi₂O₇) related to the configuration of the Si tetrahedron, which does not affect the long-range order of the β-RE₂Si₂O₇ structure. Finally, it is interesting to note that, although Sc₂Si₂O₇ shows a unique stable polymorph (β), Sc³⁺ is able to replace Y³⁺ in γ-Y₂Si₂O₇ in the compositional range 1.86?x?2 (where x is Sc_2−xY_xSi₂O₇) as well as in δ-Y₂Si₂O₇ for compositions much closer to the pure Y₂Si₂O₇.     

Formation of [Cp2TiSbMe2]2, [Cp2TiSb(SiMe3)2]2 and [Cp2TiCl]2·2Mes4Sb2

Reactions of [Cp₂Ti(btmsa)] (btmsa = bis(trimethylsilyl)acetylene) with R₄Sb₂ (R = Me, Me₃Si) give [Cp₂TiSbMe₂]₂ (1) or [Cp₂TiSb(SiMe₃)₂]₂ (2) respectively. [Cp₂TiCl]₂·2Mes₄Sb₂ (3) is serendipitously formed from [Cp₂Ti(btmsa)] and Mes₂SbH containing NH₄Cl traces.