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41.
Sm-Ru intermetallic surface alloy films were prepared by vacuum deposition and annealing of rare earth Sm on single crystal
Ru(0001) surface. The Ru 3
d
and Sm 3
d
core level spectra clearly show the formation of surface alloy layers. XPS measurements on surface alloy film revealed an
induced peak in the Ru 3
d
region at lower binding energy by 1 eV compared to the bulk Ru (elemental) suggesting an electronic effect of alloying and
Sm-Ru bond formation. The Sm 3
d
5/2
photoemission peak of Sm film consists of strong features characteristic of Sm(II) with electron configuration 4
f
6
(5
d
6
s
)
2
and Sm(III) with electron configuration 4
f
5
(5
d
6
s
)
3
.It is observed that the Sm(II) feature decreases in intensity upon alloy formation with surface Ru atoms. Oxidation of these
films with carbon monoxide indicates alloy breakdown due to the oxidation of Sm atoms selectively. Alloy oxidation also shows
a clear shift of Sm 3
d
5/2
feature. 相似文献
42.
A seed-growth method has been applied to synthesize gold (Au) and Au-silver (Ag) bimetallic nanoparticles (NP) by using 12-3-12, a cationic Gemini surfactant, as a capping agent as well as micellar template. A systematic increase in the [12-3-12] from pre- to post-micellar region (up to 5 times the critical micelle concentration, cmc) produces Au NP from spherical to large plate like structures. Keeping [12-3-12] constant (equal to 1 / 2 cmc) and increasing ascorbic acid (AA) concentration lead to the formation of core shell type Au-Ag bimetallic NP. At maximum AA concentration (i.e. [AA] = 5.6 mM), fused bimetallic Au-Ag NP are obtained. The anisotropic growth of such materials is a key factor for various applications in nanotechnology. 相似文献
43.
目的 探究双金属管材在复合过程中的受力变化以及关键工艺参数对覆管和基管壁厚分布的影响。 方法 通过有限元仿真技术和实验相结合,对铜和铝两种材料的双金属管进行旋压复合成形过程受力情况以及壁厚变化进行研究。结果 覆管由于受力面积小于基管,导致各自承受的应力具有明显差异。另外,在双金属管旋压复合时,覆管屈服强度需大于基管,否则基管不会发生减薄塑性变形。在Cu/Al双金属管旋压过程中,随着压下量的减少,双金属管的减薄以覆管为主;随着旋轮安装角的减小,双金属管的减薄以基管为主。结论 通过对压下量和旋轮安装角的优化,可实现对覆管和基管壁厚分布的良好控制。 相似文献
44.
45.
采用包套复合拉伸方法制备Pd/A1双金属丝样品,利用扫描电镜、拉力试验机等仪器,考察热处理条件对双金属丝复合界面和性能的影响.测试结果表明:Pd/Al界面易扩散,材料性能在很大程度上取决于Pd/Al界面的扩散程度:热处理温度对Pd/Al界面扩散的影响大于热处理时间,换言之,热处理温度对Pd/A1双金属丝性能的影响显著于热处理时间. 相似文献
46.
为解决双金属复合管固-液铸轧复合(SLCRB)工艺覆层熔体金属的环形均匀稳定布流问题,提出并设计了一种带有三级环形阶梯分流和锥形缓冲的环形布流器,并且基于商用软件Fluent建立了稳态布流过程的流体动力学模型,分析了布流器结构和铸轧速度对系统流场的影响,给出了获得均匀、稳定出口流场的布流器内部结构和布流条件,并用水模实验进行验证。结果表明:布流器内通道高宽比不小于1有利于均匀分流,并且锥形缓冲区的均流缓冲作用至关重要。以1.2 m/min的铸轧速度成功制备了外径为38 mm、内径为26 mm的铅-铝双金属复合管,覆层金属厚度均匀、界面结合效果良好。 相似文献
47.
Acetylene reactions over a Pd/W(111) surface are found to exhibit size effects on the nanometer scale. Upon annealing 1 ML Pd/W(111), pyramidal facets are formed having bcc(211) faces with nanometer dimensions. The facets grow as a function of annealing time and temperature. Temperature-programmed desorption (TPD) spectra of benzene and ethylene, formed reactively following acetylene adsorption, change as a function of relative facet size. Results are compared to spectra from a similar experiment performed on planar Pd/W(211). TPD of chemisorbed benzene from several different Pd/W surface morphologies are also presented. The data show that structure sensitivity is exhibited for reactively-formed ethylene and benzene, as well as for chemisorbed benzene. 相似文献
48.
Shouzhi Wang Lili Li Weidong He Yongliang Shao Yanlu Li Yongzhong Wu Xiaopeng Hao 《Advanced functional materials》2020,30(27)
Binary metal oxides (such as NiCo2O4) are regarded as attractive electrode materials for advanced energy storage devices since they offer more electrochemical activity and higher capacity than monometal oxide. However, the volume expansion and low electronic conductivity are the main bottleneck seriously hindering their application. To overcome these barriers, a novel strategy that introduces a bimetallic oxynitride layer (NiCoON) with oxygen vacancy to the surface of NiCo2O4 nanowires as an anode for Li‐ion capacitors (LICs) is proposed. The oxygen vacancy on the surface and the modulation of multiple valence states are investigated by the electron paramagnetic resonance, X‐ray photoelectron spectroscopy characterization, and first‐principles calculation. Benefiting from the merits of substantially improved electrical conductivity and increased concentration of active sites, the optimized NiCoON electrode delivers remarkable capacity (1855 mAh g?1 at 0.2 A g?1) and rate performance. The LIC device assembled by NiCoON anodes and N‐doped carbon nanowire cathodes delivers excellent rate capability, high energy density (148.5 Wh kg?1), and outstanding power density (30 kW kg?1). This study provides a new pathway for developing bimetallic oxides with an improved performance in electrochemical energy storage, conversion fields, and beyond. 相似文献
49.
本文研究了负载型双组分催化剂Pt-Bi/P中金属与载体以及金属与金属之间的相互作用,并从理论上作了较为详细的讨论。 相似文献
50.
A. Beck A. Horváth Z. Schay Gy. Stefler Zs. Koppány I. Sajó O. Geszti L. Guczi 《Topics in Catalysis》2007,44(1-2):115-121
Bimetallic AuPd catalysts were prepared by deposition of bimetallic aqueous sols formed in different ways: (i) co-reduction
of the precursor Au and Pd ions by Na-citrate/tannic acid mixture, (ii) reduction of Au(III) ions onto preformed Pd sol, and
(iii) reduction of Pd(II) ions onto a preformed Au sol. The Au/TiO2 and Pd/TiO2 samples as references were prepared from their respective sols. The structure of the samples was characterized by XRF, XRD,
XPS, TEM and CO chemisorption both in the as-prepared state and after calcination and reduction. The catalytic activities
of the calcined/reduced catalysts in the CO oxidation were compared. The presence of bimetallic crystalline phases was evidenced
in all three samples both in the as prepared and calcined/reduced states, however, various extents of Pd surface enrichment
were determined. The catalytic activity of the bimetallic samples regardless of the preparation method, is about the same
as that of the mixture of the monometallic samples. No significant synergism is suggested in the present bimetallic samples. 相似文献