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甲醇在聚苯胺修饰铂钼共沉积电极上的催化氧化 总被引:1,自引:0,他引:1
用恒电位法和循环伏安法在铂电极上分别制备了聚苯胺修饰的分散氢钼青铜电极和分散铂电极,以及聚苯胺修饰的不同铂钼比例的铂与氢钼青铜共沉积电极。用循环伏安法研究了制备电极在c(H2SO4)=0.5mol/L水溶液中的电化学行为,以及对c(CH3OH)=0.1 mol/L的催化氧化行为。其中,分散氢钼青铜电极对甲醇无催化氧化的作用,铂与氢钼青铜共沉积电极对甲醇的催化氧化效果优于分散铂电极。铂-氢钼青铜共沉积电极对甲醇氧化的催化能力与共沉积铂钼的比例有关,当制备电极所用的溶液中n(氯铂酸)∶n(钼酸钠)=2∶1时,共沉积电极对甲醇的催化氧化活性最高,此时甲醇在共沉积电极上的氧化峰电流是单纯铂电极的2.632倍。 相似文献
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铂电极在c(K2 PtCl6) =2 .5× 10 -3 mol/L、c(Na2 MoO4 ) =0 .0 5mol/L、c(H2 SO4 ) =0 .5mol/L的溶液中 ,电位为 +1 1~ - 0 2V(vs.SCE) ,以 2 0mV/s的速度循环扫描 10min ,可制得一种Pt/HxMoO3 电极。用循环伏安和电位阶跃方法研究了在所制备电极上甲醇的氧化。实验结果表明 ,所制备电极对甲醇的氧化有催化作用 :(1)氧化电位比在Pt/Pt电极上降低 0 12 5V ;(2 )氧化电流为Pt/Pt电极的 6倍。讨论了Pt/HxMoO3 电极对甲醇氧化的催化机理。 相似文献
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基于贵金属铂在甲醇燃料电池上的广泛应用,采用不同稀土金属(如钪、钇、镧系等)与铂形成合金在酸性条件下研究其对甲醇的电催化性能,并利用多壁碳纳米管增强对甲醇小分子的吸附性,提高酸性环境下甲醇的电催化氧化效率。多壁碳纳米管(MWNTs)具备纳米级别的管状结构,比表面积大,是一种优良载体,将铂-稀土合金和多壁碳纳米管充分混杂,并修饰在玻碳电极(GC)表面,具有良好的化学和物理稳定性。通过上述分析和实验制备了铂-稀土(M-Pt)合金催化剂、铂-稀土/多壁碳纳米管(M-Pt/MWNTs)催化剂。实验证明铂与稀土金属钪、钇、镧系等形成的合金的电催化性能最佳,且加入多壁碳纳米管,形成的铂-稀土/多壁碳纳米管(M-Pt/MWNTs)催化剂电化学催化效率得到明显地提升,所制备的铂-稀土合金电催化剂实用价值高。 相似文献
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纳米TiO_2-Pt修饰电极上甲醇的电催化氧化研究 总被引:8,自引:0,他引:8
用电化学法合成前驱体Ti(OEt)4,经直接水解法制备纳米TiO2膜,通过直接在纳米TiO2膜上电沉积Pt微粒得到纳米TiO2 Pt复合催化电极。扫描电子显微镜(SEM)和X射线衍射(XRD)分析结果表明,纳米TiO2的晶形为锐钛矿型,粒径约30nm,电沉积纳米Pt粒子(平均粒径约60nm)均匀地分散在纳米TiO2膜表面。循环伏安和计时电位测试表明,纳米TiO2 Pt修饰电极对甲醇的电氧化具有高催化活性和稳定性,Pt载量为0 68mg/cm2时,室温下甲醇氧化电流达到190mA/cm2,是纯Pt电极上的7 6倍。 相似文献
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采用赫尔槽试验法在柠檬酸盐体系镀液中以脉冲电沉积制备Ni-Cu合金镀层。分别采用X射线衍射仪、扫描电子显微镜及能谱仪分析了不同工艺条件下所得镀层的结构、形貌及组成,探讨了镀液中铜含量(WL)和电流密度(jk)对Ni-Cu合金镀层的铜含量(WC)及性能的影响,最终获得了WC与WL、jk之间关系的经验公式。结果表明,镀层中铜含量与镀液中铜含量呈一次线性相关,与电流密度呈幂指数关系。以经验公式为指导,综合考虑镀层外观和镀液稳定性,最终得到电沉积制备Ni70Cu30合金镀层的优化工艺参数为:WL=12%,jk=0.8A/dm2。 相似文献
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To reduce irreversible capacity and improve cycle performance of tin used in lithium ion batteries, Sn–Ni alloy nanorod electrodes with different Sn/Ni ratios were prepared by an anodic aluminum oxide template-assisted electrodeposition method. The structural and electrochemical performance of the electrode were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, cyclic voltammetry, and galvanostatic charge–discharge cycling measurement. The results showed that the copper substrate is covered with uniformly distributed Sn–Ni alloy nanorods with an average diameter of 250 nm. Different phases (Sn, Ni3Sn4 and metastable phases) of alloy nanorod formed in the electrodeposition baths with different compositions of Sn2+ and Ni2+ ions. Sn–Ni alloy nanorod electrode delivered excellent capacity retention and rate performance. 相似文献
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Direct current (DC) and pulse current (PC) electrodeposition of Pt–Co alloy onto pretreated electrodes has been conducted
to fabricate catalyst electrodes for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFC). The effect
of plating mode and pulse plating parameters on the Pt–Co alloy catalyst structure, composition and electroactivity for the
ORR in PEMFC has been investigated. The electrodeposited Pt–Co alloy catalyst indicates higher electrocatalytic activity towards
the ORR than the electrodeposited Pt catalyst. The activity of the electrodeposited Pt–Co catalysts is further improved by
applying the current in a pulse waveform pattern. The electrodeposition mode and the pulse plating parameters do not have
the significant effect on the Pt:Co composition of deposited catalysts, but show the substantial effect on the deposit structures
produced. The Pt–Co catalysts prepared by PC electrodeposition have finer structures and contain smaller Pt–Co catalyst particles
compared to that produced by DC electrodeposition. By varying the Pt concentration in deposition solution, the Pt:Co composition
of the electrodeposited catalyst that exhibits the highest activity is found. The Pt–Co alloy catalyst with the Pt:Co composition
of 82:18 obtained at the charge density of 2 C cm−2, the pulse current density of 200 mA cm−2, 5% duty cycle and 1 Hz was found to yield the best electrocatalytic activity towards the ORR in PEMFC. 相似文献
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Nopphawan Saibuathong Yupa Saejeng Kejvalee Pruksathorn Mali Hunsom Nisit Tantavichet 《Journal of Applied Electrochemistry》2010,40(5):903-910
The preparation of catalyst electrodes by electrodeposition for the oxygen reduction reaction (ORR) in proton exchange membrane
fuel cells (PEMFCs) has been studied. This work looks at the potential to apply the electrodeposition technique, in the forms
of direct current (DC) and pulse plating electrodepositions, to prepare Pt and Pt–Co alloy catalysts for membrane electrode
assemblies (MEAs). The preparation of the non-catalyst layer was found to be important for the electrodeposition of Pt catalysts.
The activities of the electrodeposited catalysts, both pure Pt and Pt–Co alloy, produced by pulse plating are substantially
higher than that of the Pt catalyst produced by DC electrodeposition. The improvement in electroactivity towards the ORR of
the electrodeposited catalysts produced by pulse plating is likely due to the finer structures of electrodeposited catalysts
which contain smaller catalyst particles compared to those produced by DC electrodeposition. A maximum performance towards
the ORR in PEMFCs was achieved from the catalysts prepared by pulse plating using a charge density of 2 C cm−2, a pulse current density of 200 mA cm−2, a 5% duty cycle and a pulse frequency of 1 Hz. 相似文献
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电沉积Ni-S、Ni-P-S合金析氢阴极的研究 总被引:1,自引:0,他引:1
在电沉积法制备Ni-S合金电极的基础上,向镀液中添加次亚磷酸钠制备了Ni-P-S合金电极。电化学测试结果表明,Ni-P-S和Ni-S合金电极的催化性能都要好于其它电极,Ni-P-S合金电极的性能随着次亚磷酸钠质量浓度的升高而降低。计算了电极的电极反应动力学参数(包括Tafel斜率b、交换电流密度0ρ和过电位η),解释了Ni-P-S合金电极和Ni-S合金电极在不同电流密度区活性不同的原因。恒电流电解表明,Ni-P-S合金电极具有较高的稳定性。电极的微观形貌用SEM进行表征,成份用能谱进行分析,通过X射线衍射分析电极的晶型结构。 相似文献
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Amorphous Pd0.35Zr0.65 alloys prepared by a melt—quench technique were investigated for their possible use as water electrolysis cathodes. The Tafel—Volmer reaction route of the hydrogen electrode reaction was concluded. Kinetic parameter values of the constituent steps were evaluated by a transient technique. The electrocatalytic activity for cathodic hydrogen evolution on the as-obtained electrode was 102 times lower than Pd foil electrodes, but it was improved after the electrodes were treated in acids, typically aqueous HF. The activity in the highest state exceeds that of Pd by one order of magnitude. SEM and XPS observations indicated that the improvement in activity is due to increased surface Pd concentration after removal of a Zr-enriched surface layer which was produced during fabrication of the amorphous alloy specimens. Crystalline alloy electrodes prepared by heat treatment of the amorphous alloy were very brittle but showed electrocatalytic activity close to that of the amorphous electrodes. 相似文献
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Electrodes modified by electrodeposition of CoTAA complexes as selective oxygen cathodes in a direct methanol fuel cell 总被引:3,自引:0,他引:3
P. Convert C. Coutanceau P. Crouïgneau F. Gloaguen C. Lamy 《Journal of Applied Electrochemistry》2001,31(9):945-952
The oxygen reduction reaction (ORR) at cobalt tetraazaanulene (CoTAA) modified electrodes was investigated. As a first approach, modified electrodes were prepared by electrodeposition of CoTAA on glassy carbon (GC). The modification of the GC surface was monitored by u.v.–vis. differential reflectance spectroscopy (UVDRS). The recorded spectra (i.e., absorbance as a function of wavelength and time) showed that the electrodeposition of CoTAA at 0.8 V vs Ag|AgCl, that is, at a potential where the TAA ligand is oxidized to TAA+, seems to produce a thin polymer film. Starting from these preliminary results, porous rotating disc electrodes (RDEs) were prepared by electrodeposition of CoTAA (0.8 V vs Ag|AgCl, 1 min) on graphite powder embedded in a recast Nafion® film. The use of a porous RDE allowed comparison of the activity and selectivity of Pt nanoparticles and CoTAA for the ORR under experimental conditions close to those of a fuel cell cathode, that is, at the catalyst|Nafion® interface. The activity towards the ORR of a porous electrode modified by electrodeposition of CoTAA is not affected when methanol is present in the electrolyte phase, whereas a noticeable decrease in the activity of Pt-based oxygen cathodes was observed under the same conditions. Half-cell life tests showed that CoTAA-modified electrodes and Pt-based electrodes have a comparable stability over a period of 90 min. 相似文献
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在工业上,稀散金属镓通常是从碱性溶液中电解提取得到的。在镓电解过程中,由于析氢副反应和传质速率低的原因导致镓电沉积的电流效率很低。本工作采用三维多孔电极电沉积镓,利用三维多孔电极发达的表面积促进镓电沉积过程,研究了不同电极材料(泡沫金属和多孔碳)的析氢特性,结合不同电解温度和电流密度下各材料的镓电沉积行为,揭示三维多孔电极上镓电沉积的特性规律。结果表明,泡沫铜和石墨毡(GF)具有较低的析氢活性,但两种电极的镓电沉积性能差别很大。其中泡沫铜表现出最佳的镓电沉积性能,在温度为40℃、电流密度为0.1 A/cm2条件下镓电沉积的电流效率(QE)达到22.5%,远高于铜片电极(10.7%);而相同条件下,GF电极的QE值仅为9.6%,低于铜片,这与电极表面的疏水性有关。具有较高析氢活性的泡沫铁、泡沫镍和网状玻璃碳(RVC)电极的镓电沉积过程受电解温度和电流密度的影响较大。在高电流密度下,泡沫铁电极表现出仅次于泡沫铜的QE值,在低电流密度下难以发生镓的电沉积;泡沫镍和RVC电极仅在低于镓熔点(20℃)的条件下发生镓的电沉积,在高于镓熔点(40℃)的条件下,由于电沉积的液态镓... 相似文献
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Electrodeposition of Ni-W-B amorphous alloys 总被引:3,自引:0,他引:3
Partial polarization curves at the glassy carbon rotating disc electrode have been used to study the electrodeposition of Ni and Ni-W alloy from citrate-containing solution. For deposition of Ni-W alloys, the partial polarization curves indicate diffusion control for nickel reduction and stoichiometric limitation for tungsten deposition by the composition of the alloy. Plating experiments show that current efficiency of the electrodeposition and composition of the resulting alloy depend on the parameters of the electrolysis. The best conditions for electrodeposition of the alloy Ni-W-B are current density of 45–50 mA cm–2, temperature of 60–70 °C, Ni(II) concentration of 20–25 mm, and pH 8.5. Pulsed galvanostatic plating at 1 Hz increased slightly the current efficiency. The concentration of Ni(II) in the solution can be self-regulated by using a nickel bipolar electrode in the cathode compartment. 相似文献
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Seok-Soon Kim 《Electrochimica acta》2006,51(18):3814-3819
Pt electrodes were prepared by direct and pulse current electrodeposition for use as counter electrodes in dye-sensitized solar cells. Scanning electron microscope and transmission electron microscope images confirmed the formation of uniform Pt nanoclusters of ∼40 nm composed of 3 nm nanoparticles, when the pulse current electrodeposition method was used, as opposed to the dendritic growth of Pt by the results from direct current electrodeposition. By applying pulse electrodeposited Pt which has a 1.86 times higher surface area compared to direct current electrodeposited Pt, short-circuit current and conversion efficiency were increased from 10.34 to 14.11 mA/cm2 and from 3.68 to 5.03%, respectively. In addition, a flexible solar cell with a pulse current electrodeposited Pt counter electrode with a conversion efficiency of 0.86% was demonstrated. 相似文献