Proton conductors of cerium pyrophosphate for intermediate temperature fuel cell

The crystal structure and proton conductivity of cerium pyrophosphate are investigated to explore its potential electrolyte applications for intermediate temperature fuel cell. Among the CeP₂O₇ thin plates, which are sintered at 300–900 °C, the 450 °C CeP₂O₇ sample exhibits superior proton conductivity under humidified conditions. Its conductivity, measured with impedance spectroscopy, is higher than 10⁻² S cm⁻¹ in the intermediate temperature range, with a maximum value 3.0 × 10⁻² S cm⁻¹ at 180 °C. When 10 mol% Mg is doped on the Ce site of CeP₂O₇, the maximum conductivity is raised to 4.0 × 10⁻² S cm⁻¹ at 200 °C. The Mg doping not only raises the conductivity, but also shifts and widens its temperature window for electrolyte applications. Ce_0.9Mg_0.1P₂O₇ is considered a more appropriate composition, with conductivity >10⁻² S cm⁻¹ between 160 and 280 °C. Accordingly, a hydrogen–air cell is built with the Ce_0.9Mg_0.1P₂O₇ electrolyte and its performance is measured. The fuel cell generates electricity up to 122 mA cm⁻² at 0.33 V using 50% H₂ at 240 °C.     

Photodegradation of DMMP and CEES on zirconium doped titania nanoparticles

The structure and photocatalytic activity of Zr doped TiO₂ nanocrystallites with a varying Zr content between 0 and 15 wt% prepared by an efficient and environmentally benign method has been studied by vibrational spectroscopy, TEM and XRD. It is shown that the presence of Zr⁴⁺ ions stabilizes the anatase structure and delays phase transformation to rutile upon annealing as well as retarding grain coarsening. All TiO₂ samples up to 13 wt% Zr doping concentration show better or similar photoreactivity compared to P25 (Degussa) for decomposition of adsorbed 2-chloroethyl ethyl sulphide (CEES) and dimethyl methylphosphonate (DMMP) in synthetic air at room temperature. The most efficient sample for photodegradation of both CEES and DMMP is shown to be titania doped with 6.8 wt% Zr. The photodegradation of CEES is faster than DMMP under the same experimental conditions. On the undoped TiO₂ sample urea residues are detected spectroscopically. Much less is detected on the Zr doped samples. Mode resolved in situ FTIR surface spectroscopy enables distinction of CEES or DMMP, decomposition products as well as the influence of residues from the particle synthesis. This facilitates extraction of intra-comparable reaction rates. Possible explanations for the improved reactivity of the Zr doped titania are discussed.     

Infrared characterization of the surface intermediates in the oxidation of toluene on vanadyl pyrophosphate catalysts

The adsorption and reaction of toluene on vanadyl pyrophosphate catalysts was studied by in situ infrared spectroscopy. Strongly adsorbed benzaldehyde and physically adsorbed cyclic anhydride species were observed at temperatures above 523 K. Water formed during reaction generates acid hydroxyl groups which cause a stronger adsorption of benzaldehyde and consecutive oxidation reactions. By co-adsorption of pyridine the acid sites are blocked and the deeper oxidation is suppressed. This revised version was published online in August 2006 with corrections to the Cover Date.     

铀氢锆堆栅距对堆芯物理性能的影响

使用铀氢锆堆（即脉冲堆）物理计算程序包ＰＲＰ－Ｓ，首先计算了栅距对有效增因子的影响，栅距与堆芯温度系数的关系，然后计算了中国核动力研究设计院设计建造的我国第一座铀氢锆反应堆的冷却温度系数，燃料温度系数和等温度系数，并且与实验值进行了比较，结果表明两者的符合得相当好。     

Ni基催化剂载体对甲烷自热重整制氢反应的影响

考察了不同载体及Zr添加量对甲烷自热重整制氢反应的影响。结果表明，载体为ZrAlO时，Ni基催化剂的催化性能最好，且CH₄转化率和H₂收率随着反应温度的升高而增大，850 ℃时CH₄转化率保持在100％，H₂收率达到79％。对不同Zr添加量的Ni基催化剂XRD谱图分析结果发现，随着Zr的添加量的增加，Al₂O₃和NiAl₂O₄的衍射峰逐渐变得弥散，而ZrO₂的衍射峰逐渐尖锐，且主要以四方相的亚稳态晶相存在。新生成的Zr₅Al₃O_0.5物种占据了本可以生成NiAl₂O₄尖晶石的位置，提高了NiO的分散性，从而提高了催化剂的活性。     

Influence of thickness and growth temperature on the properties of zirconium oxide films grown by atomic layer deposition on silicon

ZrO₂ films of thicknesses varied in the range of 3–30 nm were atomic layer deposited from ZrI₄ and H₂O–H₂O₂ on p-Si(100) substrates. The effects of film thickness and deposition temperature on the structure and dielectric properties of ZrO₂ were investigated. At 272 and 325 °C, the growth of ZrO₂ started with the formation of the cubic polymorph and continued with the formation of the tetragonal polymorph. The ratio between the lattice parameters increased with the film thickness and growth temperature. The effective permittivity, determined from the accumulation capacitance of Hg/ZrO₂/Si capacitors, increased with the film thickness, reaching 15–17 in 25-nm-thick films. The permittivity decreased with the increasing growth temperature. The hysteresis of the capacitance–voltage curves was the narrowest for the films deposited at 325 °C, and increased towards both lower and higher deposition temperatures.     

有机锆交联剂OZ—1应用研究

合成了具有延迟交联特性的有机锆交联剂ＯＺ１；介绍了ＯＺ１交联的已在胜利油田应用的３种压裂液的性能；探讨了ＯＺ１在水基聚合物冻胶堵剂和弱凝胶或胶态分散凝胶中的应用。     

焦磷酸盐滚镀铜工艺研究与应用

为提高产品质量和生产效率,降低生产成本,研究开发了焦磷酸盐滚镀铜生产工艺,研究了镀液的组成及工艺条件对镀层性能的影响,确定了镀液配方及工艺务件。生产应用结果表明,焦磷酸盐滚镀铜工艺稳定,可明显提高产品质量和生产效率,解决了原镀铜工艺存在的问题,具有较好的经济效益和社会效益。     

焦磷酸盐低锡青铜合金电镀工艺及辅助配位剂的功能

为了提高焦磷酸铜．焦磷酸亚锡电镀低锡青铜合金工艺的性能,在其镀液中加入辅助配位剂柠檬酸盐。用电化学、X射线衍射、腐蚀膏试验等方法对镀液及镀层性能进行分析。结果表明：合金镀液具有良好的分散能力,可在较宽的电流密度范围内获得色泽一致、锡含量约为10％的低锡合金镀层;电镀初始过程可实现钢铁表面的电位活化,提高了镀层与铁基体的...     

Nanocrystallized tetragonal metastable ZrO2 thin films deposited by metal-organic chemical vapor deposition for 3D capacitors

ZrO₂ is a potential candidate for the realization of 3D capacitors on silicon for future Systems-on-Chip. This paper reports on the deposition of ZrO₂ thin films by metal-organic chemical vapor deposition on planar and 3D structures. Physico-chemical as well as electrical properties of the films are investigated. It is shown that the change of phase and microstructure of the film due to annealing at 900 °C under O₂ impacts directly on the electrical performance of the capacitors. Capacitance densities are 2 nF/mm² for planar capacitors and reach 8 nF/mm² for capacitors with pores etched in silicon with a 4:1 aspect ratio.