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161.
Elise E. Switzer Tim S. Olson Plamen Atanassov Christopher J. Cornelius 《Electrochimica acta》2009,54(3):989-8003
In this work, we have investigated an aerosol-derived templated electrocatalyst for electro-oxidation of small organic molecules in alkaline media. Templated Pt-Sn electrocatalysts are compared to templated Pt catalysts both synthesized in an aerosol synthesis technique. In this synthesis approach, mono-disperse silica nanoparticles are used to template the metallic precursors. Structural and compositional analysis of the nanostructured materials are performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and BET surface area measurements. The aerosol-derived templated electrocatalysts are examined in conjunction with an anion exchange ionomer for ethanol, methanol and CO oxidation in alkaline media. The electrochemical studies include cyclic voltammetry, chronoamperometry and voltammetric adsorption of adsorbed CO. 相似文献
162.
采用共沉淀-水热法合成Tb3+掺杂Gd2Sn2O7纳米荧光材料,并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、傅里叶变换红外光谱(FT-IR)、拉曼光谱(Raman)和荧光光谱对合成产物的晶体结构、颗粒尺寸、形貌和光学性能进行研究。研究结果表明水热合成产物为单一相立方烧绿石结构Gd2Sn2O7:Tb3+晶体,产物由尺寸约为50~70 nm的一次纳米颗粒团聚而成的不规则球。激发光谱和发射光谱测试结果表明,Gd2Sn2O7:Tb3+样品可以被379 nm的紫外光有效地激发而发射出纯度高的Tb3+离子特征的绿光,在高浓度Tb3+掺杂时可观察到Tb3+发光浓度猝灭现象。在样品的激发光谱中观察到不同激发带的猝灭浓度并不相同,并对其原因进行了分析。 相似文献
163.
Sn/C复合材料的制备及其电化学性能 总被引:6,自引:0,他引:6
以煤焦油沥青为碳源、三丁基氯化锡(TBTC)为锡源,采用压力下聚合手段原位合成出Sn/C复合材料,并对它的电化学性能进行了研究。通过SEM、XRD、恒电流充放电测试等手段研究了不同Sn含量的Sn/C复合材料的形态、结构及其电化学行为,结果表明TBTC对沥青的热缩聚反应有显著的催化作用,热聚产物中吡啶不溶物(PI)组分的含量由未添加时的35.5%逐渐提高至添加量为25%时的60.3%;进一步热处理后,Sn/C复合材料中的锡由原来的SnS转化为金属锡的形式存在;其首次循环效率随着热处理温度的提高而增加,而首次充放电容量随着TBTC添加量的增加先增加后减少,在10%时达到最大的比容量值,首次充放电容量分别为674mAh/g和465mAh/g,第二次循环后,循环效率达到95%以上,是一种性能较佳的锂离子蓄电池负极材料。 相似文献
164.
Min-Na Chen Shi-Jin Ding Qing-Qing Sun David Wei Zhang Li-Kang Wang 《Journal of Electronic Materials》2008,37(6):894-900
We investigate the influence of pulse-plated Ni barriers, compared to direct current (DC)-plated Ni barriers, on the growth
of Sn whiskers in laminated Cu/Ni/Sn samples. The results indicate that the pulse-plated Ni barriers exhibit much better resistance
to Sn whisker growth than the DC-plated Ni barriers, i.e., when exposed to ambient of 60°C and 93% relative humidity (RH)
for 40 days only a few small hillocks were observed as opposed to the long whiskers and large nodules of Sn for the DC-plated
Ni barriers. The underlying mechanisms are addressed based on the texture characteristics of the plated Ni and Sn layers and
the formation of intermetallic compounds. 相似文献
165.
Thin film of silver tin sulfides (Ag–Sn–S) has been deposited on indium tin oxide coated glass (ITO) substrates using potentiostatic cathodic electrodeposition technique. New procedure for the growth of Ag–Sn–S film is presented. An electrolyte solution containing Silver Nitrate (AgNO3), Tin(II) Chloride (SnCl2) and Sodium Thiosulfate (Na2S2O3)in acidic solution (pH ~2) and at temperature of the bath 55 °C were used for the growth of Ag–Sn–S thin film. Prior to the deposition, a cyclic voltammetry technique was performed in binary (Ag–S, Sn–S) and ternary (Ag–Sn–S) systems. This study was carried out to examine the behavior of electroactive species at the electrode surface. Based on these results, the cathodic applied potential was fixed at −1000 mV versus Ag/AgCl to obtain a uniform and good adhesion of ternary thin film. After that, structural, morphological and optical performances of films have been investigated. The X-ray diffraction patterns of the samples demonstrate the presence of the orthorhombic phase of Ag8SnS6 at applied potential of −1000 mV versus Ag/AgCl. Based on the scanning electron microscopy (SEM), it was found that the surface morphology and grain size were strongly influenced by the presence of Sn and/or Ag in the electrolyte bath. The band gaps of binaries and ternary compound are evaluated from optical absorption measurements. Band gap of Ag8SnS6 determined from transmittance spectra is in the range 1.56 eV. Flat-band potential and free carrier concentration have been determined from Mott–Schottky plot and are estimated to be around 0.18 V and 2.21×1014 cm−3 respectively. The photoelectrochemical test of Ag8SnS6 was studied and the experimental observations are discussed in detail. 相似文献
166.
Surface tension and filling ability of molten metal play an important role on the shaping of the molten metal. The surface tension was calculated from wetting angles of the molten metal by the sessile drop method. The specimen for filling ability was designed and the filling ability experiments under the alternative electromagnetic field were performed. The results show that the intensity and frequency of the alternative electromagnetic field have significant effects on the surface tension of the molten metal. The surface tension of Al-6% Si alloy decreases with increasing the intensity of the electromagnetic field. For pure Sn, the surface tension decreases gradually when the frequency of electromagnetic field is reduced. The filling ability is improved by applying the alternative electromagnetic field. 相似文献
167.
氢化物发生原子荧光光度法同时测定膨化食品中的铅和锡 总被引:1,自引:0,他引:1
本文介绍在优化好的实验参数和测量条件下用氢化物发生原子荧光光度法对膨化食品中的铅、锡进行同时测定的方法,该方法的精密度Pb(1.56%~2.24%)、Sn(2.04%~3.58%),检出限Pb(0.063mg/L)、Sn(0.158mg/L),结果令人满意。 相似文献
168.
Yilin Sun Liu Qian Dan Xie Yuxuan Lin Mengxing Sun Weiwei Li Liming Ding Tianling Ren Toms Palacios 《Advanced functional materials》2019,29(28)
Recently, several light‐stimulated artificial synaptic devices have been proposed to mimic photonic synaptic plasticity for neuromorphic computing. Here, the photoelectric synaptic plasticity based on 2D lead‐free perovskite ((PEA)2SnI4) is demonstrated. The devices show a photocurrent activation in response to a light stimulus in a neuron‐like way and exhibit several essential synaptic functions such as short‐term plasticity (STP) and long‐term plasticity (LTP) as well as their transmission based on spike frequency control. The strength of synaptic connectivity can be effectively modulated by the duration, irradiance, and wavelength of light spikes. The ternary structure of (PEA)2SnI4 causes it to possess varied photoelectric properties by composition control, which enhances the complexity and freedoms required by neuromorphic computing. The physical mechanisms of the memory effect are attributed to two distinct lifetimes of photogenerated carrier trapping/detrapping processes modulated by controlling the proportion of Sn vacancies. This work demonstrates the great potential of (PEA)2SnI4 as a platform to develop future multifunctional artificial neuromorphic systems. 相似文献
169.
Xianglin Xiang Bicheng Zhu Bei Cheng Jiaguo Yu Hongjin Lv 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(26)
Herein, oil‐soluble CdS quantum dots (QDs) are first prepared through a solvent‐thermal process. Then, oil‐soluble CdS QDs are changed into water‐soluble QDs via ligand exchange using mercaptopropionic acid as capping agent at pH 13. The photocatalytic performance is investigated under the visible light irradiation using glycerol as sacrificial agent and Sn2+ as cocatalyst. No H2‐production activity is observed for oil‐soluble CdS QDs. Water‐soluble CdS QDs exhibit significantly enhanced hydrogen evolution rate. When the concentration of cocatalyst Sn2+ increases to 0.2 × 10?3 m , the rate of hydrogen evolution reaches 1.61 mmol g?1 h?1, which is 24 times higher than that of the pristine water‐soluble CdS QDs. The enhanced H2‐production efficiency is attributed to the adsorption of Sn2+ ions on the surface of CdS QDs that are further reduced to Sn atoms by photogenerated electrons. The in situ generated Sn atoms serve as photocatalytic cocatalyst for efficient hydrogen generation. 相似文献
170.
Zheng Liu Su Zhang Zhipeng Qiu Chao Huangfu Lin Wang Tong Wei Zhuangjun Fan 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(38)
Tin (Sn) is considered to be an ideal candidate for the anode of sodium ion batteries. However, the design of Sn‐based electrodes with maintained long‐term stability still remains challenging due to their huge volume expansion (≈420%) and easy pulverization during cycling. Herein, a facile and versatile strategy for the synthesis of nitrogen‐doped graphene quantum dot (GQD) edge‐anchored Sn nanodots as the pillars into reduced graphene oxide blocks (NGQD/Sn‐NG) for ultrafast and ultrastable sodium‐ion storage is reported. Sn nanodots (2–5 nm) anchored at the edges of “octopus‐like” GQDs via covalent Sn? O? C/Sn? N? C bonds function as the pillars that ensure fast Na‐ion/electron transport across the graphene blocks. Moreover, the chemical and spatial (layered structure) confinements not only suppress Sn aggregation, but also function as physical barriers for buffering volume change upon sodiation/desodiation. Consequently, the NGQD/Sn‐NG with high structural stability exhibits excellent rate performance (555 mAh g?1 at 0.1 A g?1 and 198 mAh g?1 at 10 A g?1) and ultra‐long cycling stability (184 mAh g?1 remaining even after 2000 cycles at 5 A g?1). The confinement‐induced synthesis together with remarkable electrochemical performances should shed light on the practical application of highly attractive tin‐based anodes for next generation rechargeable sodium batteries. 相似文献