花球状银催化材料的制备及其对4-硝基苯酚的催化加氢性能

通过室温下将硝酸银水溶液与含有硫酸亚铁和柠檬酸的水溶液直接混合,一步合成由银纳米片自组装而成的银花状球结构。结合X射线粉末衍射(XRD)、扫描电子显微镜(SEM)等结构表征手段,考察硝酸银水溶液的滴加速度、柠檬酸添加量等因素对产物形貌及尺寸的影响,并对银花状球的形成机理进行研究。实验结果表明,通过对硝酸银水溶液滴加速度的简单调控可以实现银颗粒形貌由薄片状到花球状的转变。此外,该形貌的微纳米材料在4-硝基苯酚加氢反应中呈现出优异的催化活性。     

Investigation of transfer ionization in collisions of partially stripped carbon ions with helium at low to intermediate velocities

The ratios of transfer ionization (TI) to single-electron capture (SC) cross sections have been measured for the collisions of partially stripped C^q+ ions (q=1--4) with He. The collision velocity ranges from 0.7 to 4.4v₀ (v₀ is the Bohr velocity). The projectile-ion and recoil-ion coincidence technique is used to separate the processes of TI and SC. The ratios reach the maximum when the velocity is about 3.7v₀ This can be explained qualitatively based on the two-step mechanism. The experimental results are also compared with the results calculated using the classical trajectory Monte Carlo (CTMC) method. The CTMC results are in agreement with the experimental data basically. The discrepancies in higher velocity region are interpreted by the effective charge effect.     

Preparation of WO3-modified TiO2 thin film by peroxo sol–gel method and its photocatalytic activity in degradation of methylene blue

Research on Chemical Intermediates - A series of WO3-modified TiO2 sols with various WO3 contents were synthesized by peroxo sol–gel method using H2O2 as the agent. The as-synthesized...     

Light harvesting analysis of a nano‐cylinder structure on crystalline silicon using the Mie scattering model

In this study, nano spheres of different diameters (d = 200 nm, 300 nm, and 400 nm) were applied in nano-sphere lithography with dry etching to construct nano-cylinder structures on the surface of crystalline silicon wafers. The structure was then bombarded by a Kaufman-type directive ion source to shape and modify the surface topography as pillar-like or cone-like structures. Finally, an AR-coating layer was deposited on the surface of the nano-cylinder structure. When the size of the nano-cylinder structure approached the wavelength of light, Mie scattering analysis was utilized to describe the optical properties formed by the structures. The results showed that the haze parameters could reach 87.8% in the visible region and 91.1% in the infra-red region.     

双抗夹心ELISA法测定水资源、食品及饲料中总甾体激素含量

基于睾丸酮丛毛单胞菌(C.test)具有降解甾体类物质的特性,其细胞中3α-羟基类固醇脱氢酶/碳酰基还原酶(3α-HSD)是诱导酶,建立了以3α-HSD的测定总甾体激素含量的双抗夹心酶联免疫反应(ELISA)方法。实验结果表明,睾丸酮类甾体激素的量在0.5～600μg/g之间,与3α-HSD酶表达量具有明显线性关系。应用这种方法对多种水资源、饲料、肉食品进行了检测。检测结果表明,松花湖水中的睾丸酮类甾体激素含量为34.5μg/g,明显高于其它水系;被测饲料中睾丸酮类甾体激素含量均大于2μg/g;肉类样品的检测结果均低于检测下限。本方法与高效液相色谱法的测定结果相符。     

典型炭材料微观结构及SO2吸附机理研究

采用SEM和低温氮吸附方法研究了碳纳米管和活性炭的表面微观形貌及孔隙结构,通过固定床研究了炭材料SO₂吸附机理。研究结果表明:活性炭大孔直接暴露于表面,中孔和微孔分布于大孔内部,"聚合"是碳纳米管的重要特征;椰壳活性炭是微孔型吸附剂,煤基活性炭孔隙主要由微孔和大孔组成,碳纳米管氮吸附有明显的毛细凝聚现象,中孔和大孔是其孔隙主要组成;活性炭SO₂吸附过程受物理吸附控制,碳纳米管SO₂吸附不同于活性炭,同时受到物理吸附和化学吸附控制;孔径小于0.7 mm的微孔是炭材料SO₂吸附的主要场所。     

Hydrogenation of p-chloronitrobenzene over NiPtB nanoalloy catalysts

NiPtB nanoalloy catalysts with various Ni contents were prepared by chemical reduction method at room temperature using NaBH₄ as reducing agent. Pt and Ni cations were completely reduced to metals, and small amount of boron was also reduced and form alloy with metals. NiPtB formed nanosized alloy structure and X-ray diffraction patterns showed its amorphous nature. The particle size distribution and the surface composition were affected by Ni/Pt ratio in the starting materials and the temperature of heat treatment. The catalytic activity of the nanoalloys was tested for hydrogenation of p-chloronitrobenzene (p-CNB). The activity and selectivity to p-chloroaniline (p-CAN) were affected by the content of Ni in the catalyst. For NiPt_0.01B catalyst, the occurrence of surface segregation of B was driven by the strain energy at high reaction temperature. For NiPt_0.03B and NiPt_0.01B catalysts, Pt segregated to the surface by H₂ affinity. Ni/Pt ratio decreased as the reaction temperature increased. The activity was essentially affected by the addition of Ni on Pt in the NiPtB catalyst, as expected, because Pt is more active than Ni for this reaction. The hydrogenation of p-CNB was very selective and yielded p-CAN exclusively on NiPtB catalysts than that on Pt catalyst.     

Hydrogenation of p-Chloronitrobenzene on Nanosized Modified NiMoB Catalysts

NiMoB alloy catalyst has been reported to be a good catalyst for the hydrogenation of p-chloronitrobenzene to p-chloroaniline. The objective of this study was to investigate the effect of additives (Pd, La, Fe and Co) on the catalytic properties of NiMoB in the hydrogenation of p-chloronitrobenzene. The catalysts were prepared by chemical reduction method using sodium borohydride as the reducing agent. The molar ratios of Ni/Mo/B/additives in the starting materials were 0.4/1/3/0.1. The catalysts were characterized by inductively coupled plasma-mass spectrometry, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalysts were tested for liquid-phase hydrogenation of p-chloronitrobenzene at 1.2?MPa H₂ pressure and 333–353?K. Adding additives decreased the particle size of modified-NiMoB catalyst, suppressed the growth of the crystalline structure of NiMoB and helped the NiMoB nanocluster maintain its amorphous state. The reaction activity is in the order of the following: Pd-NiMoB?>?La-NiMoB?>?Co-NiMoB?>?NiMoB?>?Fe-NiMoB. Pd itself is the active metal for hydrogenation, but NiPd bimetallic alloy was too active resulting in low selectivity of chloroaniline. The other additives were in the form of hydroxide and acted as a spacer to prevent NiMoB catalysts from sintering and aggregation.     

对氯硝基苯在含镧的镍钼硼奈米触媒上的氢化反应

钼和镧是好的镍硼触媒的促进剂, 对于对氯硝基苯氢化反应有好的效果, 因此同时加入钼和镧在镍硼触媒上应该是有趣的研究题目. 本研究利用化学还原法制备了一系列含有不同量镧的镧钼镍触媒, 醋酸镍、钼酸胺及硝酸镧同时加入含有甲醇的水溶液中. 以X光绕射, 穿透式电子显微镜、高分辨率电子显微镜及X光光电能谱仪鉴定了这些触媒. 对氯硝基苯氢化反应是在批次反应器中于333 K、1.2 MPa氢气压力及500 r/min转速下操作. 即使在镍钼硼中加入很少量的镧, 对提高活性及对氯苯胺的选择性都有显著的效果, 加入适量的镧可以抑制镍钼硼的长范围的结晶排列, 并保持镍钼硼在非结晶状态. 镧以氧化态存在, 其功效为阻隔物, 避免镍钼硼聚集, 但是过量的镧会有相反的效果, 镧和镍的适当比例是0.2.     

三维多枝雪花状银粉的制备及催化性能

室温下,以聚乙烯醇为保护剂,采用抗坏血酸还原硝酸银,于水相中一步合成出三维多枝雪花状银粉。结合X射线粉末衍射（XRD）、扫描电子显微镜（SEM）等结构表征手段,对三维多枝雪花状银粉的微观结构进行详细分析,在此基础上提出其可能的形成机理。此外,三维多枝雪花状银粉在4-硝基苯酚催化加氢反应中还表现出优异的催化活性。