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21.
A novel bisupporter binetal catalyst PVP-PdCl2-SnCl4/MonK10-PEG400,using for dehalogenation of insoluable aromatic halides in aqueous system,has shown high dechlorination activity and selectivity,without any organic solvent or phase transfer catalyst.The conversion of aromatic chlorides can reach 100%.The catalyst is easy to prepare and has good reusability.  相似文献   
22.
Dendrimers, well-defined hyper-branched macromolecules with characteristic globular structure, have emerged as an attractive material in the field of catalysis and have been considered as a new type of host for the accommodation of guest molecules by virtue of their three-dimensional structure having interior void space. In line with the prospect of dendrimer as a nanoreactor, various metal nanoparticles have been successfully prepared via encapsulation in or formation of particles surrounded by dendrimer branches. However, it is worth noting that most of the previous studies have been confined to the monometallic nanoparticles, and bimetallic nanoparticles have been scarcely exploited yet. In this article, we present the synthesis and characterization of dendrimer-templated bimetallic nanoparticles and their application to catalysis.  相似文献   
23.
对四层对称轧制复合时的压下率变化规律进行了研究,发现四层对称轧制复合时,同一次复合的两块复合板的压下率并不完全相等(ε1≠ε2),四层复合的总压下率εΣ介于两块复合板的压下率ε1与ε2之间,并且总压下率εΣ等于两块复合板的平均压下率。  相似文献   
24.
以弹塑性力学理论为基础,对双金属复合板在平面应力状态下的拉伸回弹过程进行解析,得出回弹残余曲率及残余应变中性轴偏移量的解析方程,继而结合有限元仿真和试验分析钢-铝复合板的拉伸回弹变形行为。研究表明,复合板拉伸回弹后呈现纯弯曲状态,残余曲率随着载荷的增大而增大,对于任意材料的双金属复合板均存在一个复合配比值,在该值下拉伸回弹产生的残余曲率最大。  相似文献   
25.
在自行设计和制造的双金属复合材料连铸设备上,通过工艺参数的合理配置,成功制备出尺寸为150mm×120mm×100mm的AlSi/AlMn双金属复合材料铸坯。分析了复合铸锭的宏观和显微组织、界面附近的元素成分以及界面结合强度和硬度分布。结果表明,复合界面为冶金结合,所制备复合材料的微观组织与化学成分分布及硬度之间有良好的对应关系。  相似文献   
26.
采用简单的水热法制备了多面体钒酸铋(BVO)材料,又通过化学还原法首次在BVO上原位合成了一种小尺寸的AgNi双金属助催化剂并研究了其光催化性能。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外可见漫反射光谱(UV-Vis DRS)、X射线光电子能谱(XPS)、光致发光(PL)光谱、N2吸附-脱附等手段对制备的AgNi/BVO材料的理化性能进行了表征。结果表明,AgNi双金属广泛负载在这种特殊形貌的BVO多面体表面,大大增加了金属的附着位点,同时AgNi负载也提高了BVO的结晶性。银表面等离子体谐振效应与镍的共格界面效应增强了BVO催化剂对可见光的吸收,增强了光生电子的分离,提高了光催化活性。光催化降解MB (亚甲基蓝)实验表明,当Ag、Ni的质量比为3∶1时,AgNi/BVO的催化活性最高,在可见光照射下其反应速率常数是BVO的5.4倍,该光催化剂在4次循环后仍能保持良好的光催化活性。  相似文献   
27.
A series of Mn/Ce-based bimetal-organic frameworks, recorded as MCDx (x = 1, 2, 4, 6), were prepared by a solvothermal synthesis method to explore their effects and performance in the synergistic catalysis of toluene under the irradiation of non-thermal plasma. The catalytic properties of different manganese loadings in MCDx for degradation of toluene were investigated. The microphysical structures of the material were analyzed by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results showed that a MCDx coupling with non-thermal plasma can greatly improve the degradation efficiency, the energy efficiency and the CO2 selectivity, and could also significantly reduce the generation of O3 in the by-products. Among the test samples, MCD6 with Mn:Ce = 6:1 (molar ratio) showed the best catalytic performance and stability, exhibited toluene catalytic efficiency 95.2%, CO2 selectivity 84.2% and energy efficiency 5.99 g/kWh, and reduced O3 emission concentration 81.6%. This research provides a reference for the development and application of synergistic catalysis based on bimetal-organic frameworks and non-thermal plasma in the reduction of industrial volatile organic compounds.  相似文献   
28.
The bimetal-bearing (CePt or LaPt) 12-tungstophosphoric acid (H3PW12O40 (PW)) catalysts supported on dealuminated USY zeolite (DUSY) were prepared by impregnation and characterized by XRD, BET, IR, and H2-chemisorption. Their catalytic activities were tested in the hydroisomerization of n-heptane with a continuous atmospheric fixed-bed reactor. After the steam treatment combined with the acid leaching, as well as the supporting with PW and the bimetals, the DUSY support retains the Y zeolite porosity and the PW well keeps its Keggin structure in catalysts. The doping of Ce into the catalysts enhances the dispersion of Pt on the catalyst surface. The Pt-bearing PW catalysts doped with Ce or La, especially Ce, exhibit much higher catalytic activity and selectivity than the catalysts without dopants at lowered reaction temperatures. At the optimal reaction conditions, i.e., the reaction temperature of 250℃ and WHSV of 1.4 h1, the catalyst with a Pt loading of 0.4%, PW loading of 10% and a molar ratio of Ce to Pt of 15:1 shows a conversion of n-heptane of 70.3% with a high selectivity for isomerization products of 94.1%.  相似文献   
29.
Elimination of VOCs by catalytic oxidation is an important technology. Here, a general synergistic capture-bonding superassembly strategy was proposed to obtain the nanoscale dispersed 5.8% PtFe3−CeO2 catalyst, which showed a high toluene oxidation activity (T100=226 °C), excellent catalytic stability (125 h, >99.5%) and a good water resistance ability (70 h, >99.5%). Through the detailed XPS analysis, oxygen cycle experiment, hydrogen reduction experiment, and in-situ DRIFT experiment, we could deduce that PtFe3−CeO2 had two reaction pathways. The surface adsorbed oxygen resulting from PtFe3 nanoparticles played a dominant role, due to the fast cycling between the surface adsorbed oxygen and oxygen vacancy. In contrast, the lattice oxygen resulting from CeO2 nanorods played an important role due to the relationship between the toluene oxidation activity and the metal-oxygen bonding energy. Furthermore, DFT simulation verified Pt sites were the dominant reaction active sites during this reaction.  相似文献   
30.
双金属Hg2+和Cu2+对木瓜蛋白酶活性与构象的影响   总被引:1,自引:0,他引:1  
研究双金属Hg2+和Cu2+对木瓜蛋白酶活性与构象的影响.利用FT-IR、荧光发射以及紫外吸收光谱探讨Hg2+和Cu2+处理与木瓜蛋白酶二级结构变化的关系.研究结果表明:金属离子与木瓜蛋白酶活性之间存在剂量-效应关系,表现出低剂量促进,高剂量抑制的Hormesis现象.低浓度下,双金属Hg2+和Cu2+表现出协同激活效应;高浓度下,Cu2+的添加屏蔽了Hg2+的抑制作用.双金属离子浓度为10-6 mol/L Hg2+和10-8 mol/L Cu2+时,对酶的激活效应最大,其处理的木瓜蛋白酶的有序结构(α-螺旋和β-折叠)含量最高,二级结构最稳定,酶与底物亲和力最强,活性最高.当双金属离子浓度为10-4 mol/L Hg2+和10-4 mol/L Cu2+时,其抑制力最强,处理的木瓜蛋白酶有序结构含量最低,二级结构破坏,活性最低.木瓜蛋白酶分子构象的有序度与其活性呈正相关.  相似文献   
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