Effect of Pt Incorporation into Ni/ZrO2–SO 4 = /Al2O3 Catalyst for n-Butane Isomerization

Three Ni/ZrO₂–SO₄⁼/Al₂O₃ catalysts with different concentrations of platinum (0.2, 0.3 and 0.4 wt%) were prepare and tested for n-butane isomerization reaction at 338 K, in absence and in presence of hydrogen. The results shown that, at low temperature, platinum contributes to the olefin or butyl ion formation and the reaction follows a bimolecular pathway. However, when the reaction occurs in the presence of hydrogen, the formation of butyl ions is inhibited. The main feature of platinum addition is the stabilization of the catalytic activity, which is indicated by the slow deactivation constants compared to that of the unpromoted catalyst.     

Vapor-Phase Alkylation of Toluene with Isopropanol over Mg/Al, Ni/Al and Cu/Al Hydrotalcites (Layered Double Hydroxide)

Vapor-phase isopropylation of toluene has been carried out over Mg/Al, Ni/Al and Cu/Al calcined hydrotalcites (CHTs). Reaction conditions were optimized for alkylation by varying temperature, weight hourly space velocity and reactant mole ratio. Side-chain alkylation is found to be more predominant than ring alkylation over Mg/Al CHT, while Ni/Al and Cu/Al CHTs favored ring alkylation. The main products were isobutylbenzene and cymene. The combined participation of acidic and basic sites of the materials is found to be crucial for both side-chain and ring alkylation of toluene with isopropanol. An X-ray diffraction pattern of the resulting oxide indicates a diffuse MgO structure. The incorporation of small amounts of Al³⁺ to MgO generates new surface Lewis acid--base pair sites.     

甲烷部分氧化制合成气催化剂的研究进展

综述了甲烷部分氧化制合成气的研究意义和现状，从金属活性组分，载体效应，载量选择，助剂添加和制备方法等因素对催化剂活性的影响及研究进行了系统。结合本课题组的研究结果及文献报道，分析了Ni基催化剂的失活特性，并提出使用等离子体技术对Ni基催化剂进行改笥处理，以提高其催化稳定性的技术展望。     

丁二酮肟吸光光度法测定陶瓷色釉料中的镍

当有氧化剂存在时，在氨性溶液中，镍与丁二酮肟生成酒红色的络合物。借此可作镍的比色测定。若离子本身有颜色，则影响测定，但可用空白校正。     

钛基体化学镀镍及其耐蚀性能

采用化学镀在钛基体上制备Ni-P合金镀层.研究了活化时间、镀液pH值、热处理温度及时间对镀层的影响.用动电位极化曲线法比较镀层的耐均匀腐蚀性能,并用X-射线衍射仪和扫描电子显微镜分别研究镀层结构和表面形貌.结果表明,以HF为主剂的活化液,时间60 s,pH值4.8～5.2的活化工艺以及250 ℃、保温2 h的热处理为最佳工艺.镀层具有较高的耐蚀性能,属于非晶和微晶组成的混晶结构.借助于正交试验,确定了最佳工艺.     

Ni/Al_2O_3覆膜方法

阐述了Ni/Al2 O3 复合颗粒在生产中的应用 ,讨论了在Al2 O3 陶瓷颗粒上形成Ni膜的三种方法 ,分析了这些方法的优缺点。     

In situ impedance study of the Y-Ni thin film under electrochemical hydrogenation

A thin film of yttrium Y (150 nm) protected by a 6 nm coating of nickel Ni on a glass substrate was completely hydrogenated in a 1 M NaOH electrolyte at a constant negative current until the transparent Y tri-hydride phase was achieved and hydrogen gas evolution from the electrode began. A series of impedance measurements were performed in situ during the electrochemical experiment to study the properties of the system as dependent on hydrogenation degree and time of relaxation. The equivalent electrical circuit (EEC) simulations were performed with a Randles-like scheme R₀[R₁CPE₁], where R₀ is the thin film electrode resistance, R₁ the charge transfer resistance and CPE₁ is the capacitive constant phase element. The behavior of all the components of the EEC undergoes a clear transition when the hydrogenation degree of the electrode is approximated to its maximum value (H to Y ratio 2.7) and electrochemical process changes from hydrogen uptake to hydrogen evolution.     

Pulse study of methane partial oxidation to syngas over SiO2-supported nickel catalysts

Methane was pulsed over pure CuO and NiO as well as Cu/La₂O₃ and Ni/La₂O₃ catalysts at 600° C. Results indicate that the mechanisms for methane activation over copper and nickel are quite different. Over CuO, methane is converted to CO₂ and H₂O, most likely via the combustion mechanism; whereas metallic copper does not activate methane. Over NiO in the presence of metallic nickel sites, methane activation follows the pyrolysis mechanism to give CO, CO₂, H₂ and H₂O. Similar results were obtained over the Cu/La₂O₃ and Ni/La₂O₃ catalysts. XRD investigations indicate that copper and nickel existed as CuLa₂O₄ and LaNiO₃ respectively in the La₂O₃-supported catalysts. The effect of La₂O₃ on the activation of methane is discussed.     

Theoretical studies of displacement deposition of nickel into porous silicon with ultrahigh aspect ratio

A model is developed to address the uniformity of displacement deposition of nickel inside porous silicon with an ultrahigh aspect ratio as high as 200. The nickel distribution is treated as a current distribution issue as in electrodeposition. It is shown that the deposition distribution along the pore depth exhibits a strong dependence on a polarization parameter ξ. High values of ξ correspond to mass transport limitations and lead to non-uniform distributions, whereas small ξ values, representing interfacial reaction control, produce uniform distributions. Non-uniform deposition primarily occurs at an initial stage in which the reaction is dominated by mass transfer. As the deposition process continues, the deposition rate drops to a low value, and the deposition uniformity shifts from Ni²⁺ mass transport limitations to its interfacial reaction control, leading to uniform Ni²⁺ concentration and deposition rate distributions. It is predicted that the non-uniformity at the initial stage could be remedied by increasing the bulk concentration of the nickel ions and decreasing the plating bath pH. In addition, the uniformity of the deposition distribution can be significantly improved by introducing inhibiting additive coumarin to the plating solution.     

The effect of vacuum evaporation plating on phase structure and electrochemical properties of AB5–5 mass% LaMg3 composite alloy

In this paper, Cu, Al and Ni were plated on the AB₅–5 mass% LaMg₃ composite hydrogen storage alloy using a vacuum evaporation plating method. The phase structure and the electrochemical properties were investigated. The X-ray diffraction (XRD) analysis shows that the phase structure is not changed obviously after the plating Cu, Al and Ni on the composites. The electrochemical tests show that maximum discharge capacity, high rate dischargeability (HRD), dischargeability at low temperature and cyclic stability was improved by vacuum evaporation plating Cu, Al and Ni. Maximum of discharge capacity of the AB₅–5 mass% LaMg₃ composite alloy plating Ni can reach 351 mAh/g, which is 3.5% higher than that of the untreated. HRD at I_d = 1200 mA/g of the composite alloy plating Cu is 45.0% of that at 60 mA/g, which is 20.4% higher than the untreated. Discharge capacity of the composite alloy plating Cu at low temperature 233 K is 205 mAh/g, which is 57.3% of that at 298 K, and it is much higher than 36.8% of the untreated composites. The discharge capacity retention of the composite alloy plating Al after 200 cycles is 7.8% higher than the untreated.