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排序方式: 共有623条查询结果,搜索用时 46 毫秒
41.
PdY8.5Ru0.19合金是用于氢同位素分离的膜材料,但涉氚操作后,衰变3He会滞留在合金膜中并形成氦泡,影响其宏观性能.为了解PdY5.5Ru0.19合金膜贮氚老化后,3He在合金膜中的存在形式及分布状态.利用TEM观察分析了贮氚老化45和290 d的PdY8.5Ru0.19合金膜.实验结果表明:在老化45 d的样品中,观察到分布均匀,直径约1 nm的氦泡,同时存在高密度的位错及位错环.在老化290 d的样品中,氦泡直径略微增加,达1.2~1.4nm,且分布均匀,但位错及位错环密度降低.同时,在合金膜中也观察到因氦泡存在而产生的微裂纹与褶皱,这有可能是导致合金膜贮氚后力学性能下降的原因. 相似文献
42.
Ru incorporated Ni-MCM-41 mesoporous catalysts for dry reforming of methane: Effects of Mg addition, feed composition and temperature 总被引:1,自引:0,他引:1
S. Yasyerli S. FilizgokH. Arbag N. YasyerliG. Dogu 《International Journal of Hydrogen Energy》2011,36(8):4863-4874
Nickel incorporated MCM-41-like mesoporous materials, which were synthesized following a one-pot hydrothermal route, were promoted by Ru and Mg in order to improve their catalytic performances for dry reforming of methane. In this study, Ni-MCM-41 based catalysts (with a Ni/Si molar ratio of 0.2), containing different amounts of Ru (0.5-3.0 wt%) and Mg (1 and 5 wt%) were prepared by using sequential impregnation of Ru and Mg into Ni-MCM-41. Dry reforming of methane was studied in a tubular flow reactor in the temperature range of 500-600 °C with different CH4/CO2 ratios in the feed stream. Quite high hydrogen yield values and improved stability of these catalysts indicated the promoting effects of Ru for the Ni-MCM-41 type catalysts. Ru incorporation (1.0% Ru) was shown to improve H2 yields. Mg impregnation into 1.0Ru@Ni-MCM-41 improved catalytic performance by increasing CH4 conversion and decreasing the contribution of reverse water gas shift reaction, especially at initial times (first 60 min). Coke formation by decomposition of CH4 contributed to the hydrogen selectivity, but did not cause significant change in catalytic performance, especially at longer reaction times. 相似文献
43.
Propane conversion over a Ru/CGO catalyst and its application in intermediate temperature solid oxide fuel cells 总被引:1,自引:0,他引:1
M. Lo Faro D. La Rosa G. Monforte V. Antonucci A.S. Arico P. Antonucci 《Journal of Applied Electrochemistry》2007,37(2):203-208
A Ru/CGO catalyst was investigated in combination with a Cu current collector for the direct electro-oxidation and internal
reforming of propane in a solid oxide fuel cell. The electrochemical power densities for the direct oxidation were larger
than in the internal reforming process at 750 °C. The electrochemical performance in the presence of propane was significantly
affected by the polarization resistance which was about three times larger than that obtained for the SOFC fed with hydrogen
at 750 °C. However, out-of-cell steam reforming tests showed a C3H8 conversion to syngas approaching 90% at 800 °C. Thus, significant enhancements may be achieved by properly optimizing the
anode structure. No formation of carbon deposits was observed both upon operation of the anode in the direct oxidation and
internal reforming processes at 750 °C. 相似文献
44.
Chloromethylated styrene-divinylbenzene copolymer was chemically modified with ethylenediaminetetraacetic acid ligand. Catalytically
active polymer containing Ru(III) moieties were synthesized from this polymeric ligand. They were characterized using FTIR,
UV-vis, SEM, ESR and TGA. Other physico-chemical properties such as bulk density, surface area, moisture content and swelling
behaviour in different solvents were also studied. The polymer bound complex was used to study hydrogenation of 1-hexene ton-hexane under mild conditions. Influence of [1-hexene], [catalyst], temperature and nature of the solvent on the rate of the
reaction was investigated. A rate expression is proposed based on the observed initial rate data. Recycling efficiency of
the catalyst has also been studied. 相似文献
45.
The interaction of nitrous oxide with ruthenium surfaces was studied in order to develop a fast and reliable method for the determination of the metallic surface area and dispersity of ruthenium catalysts as alternative to the established chemisorption methods using hydrogen, carbon monoxide or oxygen as probe molecule. Studies of the temperature dependence of the reactive or dissociative chemisorption of nitrous oxide using pulse technique showed that an oxygen monolayer of almost constant stoichiometry is formed in a narrow temperature range around 403 K. However, so-called ‘rest nitrogen peaks' were observed after saturation of an O-monolayer revealing a small additional nitrous oxide conversion which could be attributed to formation of subsurface oxygen by means of back-titration of the oxygen totally uptaken. This additional nitrous oxide consumption can be minimised by an adjustment of both the N2O-sampling loop volume and the catalyst sample weight in order to obtain an oxygen monolayer saturation by few pulses, and moreover, it can be considered as a correction for the calculation of the oxygen monolayer. A specific nitrous oxide consumption of 13.5 μmol/m2Ru has been determined on ruthenium black by means of alternating measurements of the nitrogen physisorption and N2O-pulse chemisorption. The reliability of the new method for characterisation of the dispersity or surface area of supported ruthenium was proved with ruthenium highly dispersed on γ-alumina. 相似文献
46.
采用磁控溅射方法,制备了以不同厚度Ru薄膜为籽晶层的CoCrPt-SiO2垂直磁记录薄膜。利用原子力显微镜(AFM)、透射电镜(TEM)分析Ru薄膜的结构和形貌,并研究了其结构对CoCrPt-SiO2薄膜表面形貌、粗糙度及结构的影响。结果表明,CoCrPt-SiO2记录层的晶粒尺寸和粗糙度均随着Ru籽晶层厚度的增加而增加,薄而粗糙的籽晶层适合于高密度磁记录介质。对于CoCrPt-SiO2记录层晶粒的优化,厚度为70nm的Ru籽晶层有利于记录层薄膜晶粒的完全隔离,从而提高了磁记录性能。 相似文献
47.
以类水滑石为前驱体,采用共沉淀法制备了不同Ru含量的xRu/Mg(Al)O催化剂(x=1,2,4),采用XRD、H2-TPR和CO脉冲吸附等表征催化剂结构和Ru金属分散度,并评价Ru含量对CH4-CO2重整反应活性与稳定性的影响。XRD与CO脉冲吸附结果表明,Ru含量增加时,还原后Ru金属颗粒的表面活性位数目增加,但分散度降低,Ru金属的粒径增大。活性测试结果表明,Ru质量分数为2%时,催化剂活性最高。Ru质量分数为1%时,催化剂具有较好的稳定性,归属于高分散Ru金属颗粒与Mg(Al)O载体之间的强相互作用。 相似文献
48.
49.
50.
Lihua Zhu Yingying Jiang Jinbao Zheng Nuowei Zhang Changlin Yu Yunhua Li Chih‐Wen Pao Jeng‐Lung Chen Chuanhong Jin Jyh‐Fu Lee Chuan‐Jian Zhong Bing H. Chen 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(34):4385-4393
The design of an ideal heterogeneous catalyst for hydrogenation reaction is to impart the catalyst with synergetic surface sites active cooperatively toward different reaction species. Herein a new strategy is presented for the creation of such a catalyst with dual active sites by decorating metal and metal oxide nanoparticles with ultrafine nanoclusters at atomic level. This strategy is exemplified by the design and synthesis of Ru nanoclusters supported on Ni/NiO nanoparticles. This Ru‐nanocluster/Ni/NiO‐nanoparticle catalyst is shown to exhibit ultrahigh catalytic activity for benzene hydrogenation reaction, which is 55 times higher than Ru–Ni alloy or Ru on Ni catalysts. The nanoclusters‐on‐nanoparticles are characterized by high‐resolution transmission electron microscope, Cs‐corrected high angle annular dark field‐scanning transmission electron microscopy, elemental mapping, high‐sensitivity low‐energy ion scattering, and X‐ray absorption spectra. The atomic‐scale nanocluster–nanoparticle structural characteristics constitute the basis for creating the catalytic synergy of the surface sites, where Ru provides hydrogen adsorption and dissociation site, Ni acts as a “bridge” for transferring H species to benzene adsorbed and activated at NiO site, which has significant implications to multifunctional nanocatalysts design for wide ranges of catalytic reactions. 相似文献