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钛、玻璃碳基体中离子注入5×10~(16)×10~(1(?)Ni~+离子cm~(-2).在30%KOH溶液中测试这些电极对氢析出反应的电催化性能.结果表明,离子注入电极的催化活性优于未注入的钛、玻璃碳基体.由极化测量求得动力学参数j、b和E.这些数据表明,在离子注入电极上,氢析出反应的速度决定步骤与镍电极相似,由电化学放电步骤控制。AES测量表明,镍在钛基体中的深度分布近似高斯分布,在阴极极化过程中,注入的镍没有损失,但明显地移向深处.用XPS研究注入前后Ni_(2p)和Ti_(2(?))电子结合能所产生的位移表明,离子注入可能在基体表面形成合金. 相似文献
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离子注入不受相律和化学平衡的限制,也不受离子源和基体种类的约束,注入离子的能量和剂量精确可控,因而它是实现材料表面改性最有效的方法之一.自Grenness等发现注铂的钨电极,对H~+还原的电催化性能与纯铂接近之后,Wolf等将注入的Pt/RuO_2、Pt/C、Pt/WC电极用于H~+、O_2的电化学还原及甲酸的电化学氧化,其催化活性和稳定性均优于光滑的纯铂电极、Thompson等在钛基上注铂,用于催化析氢也得到类似的效果。近期文献报导,用热处理或电沉积方法制备的Ni-Mo、Ni-Mo-V 合金电极有很低的析氢超 相似文献
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酸性溶液中离子注入钯的玻璃碳电极上硝基苯的电化学还原 总被引:3,自引:0,他引:3
用循环伏安法在离子注入钯的玻璃碳电极上,研究了硝基苯在0.5mol/L硫酸溶液中的电还原过程,通过AES测量了离子注入电极的表面组成和各元素的浓度-深度分布,在40keV下,注入剂量为1×l0 ̄(17)离子/cm_2的钯注入到玻璃碳(GC)中可产生钯原子最大百分含量为20%的近表面区。原基体注入钯后比未注入的GC对硝基苯(NB)的电还原有更高的活性,用气相色谱法检测到NB的还原产物苯胺,讨论了硝基苯在酸性溶液中电化学还原机理。 相似文献
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钛基体中离子注入镍和钼的电催化活性 总被引:2,自引:0,他引:2
Grenness等发现,铂离子注入钨基体中,对H~+还原产生的电催化性能与纯铂相近,此后,Wolf等用离子注入和离子束混合技术制作了多种电极,其中Pt/RuO_2、Pt/C、Pt/WC电极用于H~+和O_2的电还原以及甲醇和甲酸的电氧化,其催化活性和稳定性均优于光滑的纯铂电极,目前,在其它方法制作的析氢电极材料中,最可能用于工业电解槽的为NiMo合金电极和复合Raney镍合金电极,本工作将镍和钼离子注入到钛基体中,研究了此电极在30 wt%KOH溶液中析氢电催化行为,并通过电子探针显微分析(EPMA)和X射线光电子能谱(XPS)分析,检测了离子注入电极的表面成分、注入元素的浓度分布及价态。 相似文献
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研究了铁基体离子注入钯后的腐蚀行为。钯离子注入剂量为1×10^6~1×10^18离子.cm^-2注入能量40deV.在pH=5.0的0.5mol/L NaAc/HAc缓冲溶液中,用动电位扫描法测量了注钯后的铁的阳极溶解过程,用开腐蚀电位与浸泡时间的关系研究了修饰材料的耐蚀性。结果表明,钯离子的注入降低了铁的临界钝化电流,在pH=5.0的醋酸盐缓冲溶液中保持较好的钝性。但当注入电极表面的氧化膜被还原 相似文献
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电解煤浆制氢阳极的制备及电催化活性研究 总被引:2,自引:0,他引:2
将钛片进行预处理, 用处理后的钛片作为电极基体, 然后用循环伏安法在钛基体上沉积制备了Pt/Ti, Pt-Ru/Ti, Pt-Ir/Ti, Pt-Ru-Ir/Ti催化电极, 通过扫描电镜(SEM)、X射线衍射(XRD)、电子能谱(EDS)以及等离子发射光谱(ICP)等方法对所制备电极进行了表征, 包括电极表面形貌、组分的沉积状态、催化层成分组成以及电极寿命等; 在煤浆电解过程中, 采用两电极体系, 对所制备电极的电催化活性进行了测试. 结果表明: 所制备的电极催化活性都高于同面积的铂片电极, 含有Ru, Ir的二元催化电极的活性好于镀铂催化电极. 在一定范围内, 随着Ru元素比例增大, 电极活性增强, 而Ir元素含量过大, 电极活性反而稍微降低, 所以Pt-Ir(1∶0.5)/Ti, Pt-Ru(1∶5)/Ti两电极的催化活性相对较好. 本文所制备的三元催化电极的催化活性低于二元催化电极. Pt-Ru/Ti电极催化活性最好, 相同条件下具有最大的电解电流, H2的电解效率可达95%以上. 相似文献
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辅酶I(NAD )在0.005moL/LTris 0.01moL/LNaCl溶液(pH7.0)中,于钴离子注入修饰碳纤维电极上出现一个S形的还原波,半波电位为-1.45V(vs.SCE)。峰电流与NAD 的浓度在2.38×10-5~4.76×10-4mol/L(r=0 9992)和4.76×10-4~1.78×10-3mol/L(r=0.9982)之间成线性关系,检出限为1.19×10-5mol/L,回收率在96.7%~103.4%之间。用线性扫描、循环伏安法研究了钴离子注入修饰碳纤维电极上NAD 的电化学行为。电极反应机理为:NAD e NAD·;NAD· e H NADH;2NAD·→NAD2。另外,钴离子注入修饰碳纤维电极对NAD 具有电催化作用。 相似文献
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电解液中金属离子会影响钒液流电池的电化学性能。本文采用循环伏安法和电化学阻抗谱研究了正极液中Mn2+浓度对V髨/V(Ⅳ)电对的氧化还原过程影响规律,发现Mn2+在正极液中没有发生副反应,但严重影响V髨/V(Ⅳ)的反应活性、电极反应可逆性、离子扩散与电荷转移反应等电化学性能。循环伏安测试结果表明Mn2+浓度为0.04-0.13 g.L-1时,V髨/V(Ⅳ)电对电极反应可逆性和反应活性较高,钒离子扩散系数由参照溶液中的8.89×10-7-1.098×10-6增大至1.302×10-6-1.800×10-6 cm2.s-1,提高了-60%;电化学阻抗测试结果表明Mn2+浓度为0-0.04 g.L-1时,V髨/V(Ⅳ)电对电极反应阻抗和界面阻抗均较参照溶液中的增加不明显,但当Mn2+浓度增至0.07 g.L-1时,上述阻抗值较参照溶液增大了25%-28%。基于二者结果,Mn2+对电极反应有不同程度的负面影响,但是适当的Mn2+浓度有利于钒离子的扩散。 相似文献
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A novel flow-injection amperometric method was proposed for the sensitive and enzymeless determination of hydrogen peroxide based on its electrocatalytic reduction at a palladium nanoparticle-modified pretreated pencil graphite electrode in a laboratory-constructed electrochemical flow cell. Cyclic voltammograms of the unmodified and modified electrodes were recorded in pH 7.0 phosphate buffer containing 0.10 M KCl at a scan rate of 50?mV s?1 for the investigation of electrocatalytic reduction of hydrogen peroxide at the palladium nanoparticle-modified pretreated pencil graphite electrode. Cyclic voltammograms of the pretreated pencil graphite electrode revealed an irreversible oxidation peak and a weak reduction peak of hydrogen peroxide at +1100?mV and –450?mV vs. an Ag/AgCl/KCl saturated reference electrode. However, the reduction of hydrogen peroxide was observed at –100?mV with an increase in current in the cyclic voltammograms of the palladium nanoparticle-modified pretreated pencil graphite electrode compared to the unmodified electrode. These results indicate that the palladium nanoparticle-modified pretreated pencil graphite electrode exhibits efficient electrocatalytic activity for the reduction of hydrogen peroxide. A linear concentration range was obtained between .01 and 10.0?mM hydrogen peroxide with a detection limit of 3.0 µM from flow injection amperometric current–time curves recorded in pH 7.0 phosphate buffer at –100?mV and a 2.0?mL min?1 flow rate. The novelty of this work relies on its use of a laboratory-constructed flow cell constructed for the pencil graphite electrode using these inexpensive, disposable, and electrochemically reactive modified electrodes for the amperometric determination of hydrogen peroxide in a flow injection analysis system. 相似文献
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A carbon ionic liquid electrode modified with a thin layer of silica sol? gel containing phosphinite ionic liquid was prepared for deposition of palladium nanoparticles. Palladium nanoparticles were formed easily by simple contact of the modified electrode with palladium chloride solution. The novel material overcomes the shortcomings of conventionally modified electrodes with a thin layer of silica sol? gel, due to the existence of ionic liquid in silica matrix. A crack‐free sol? gel matrix was obtained and also, the uniform porous structure of the ionic liquid‐sol? gel matrix resulted in a fast mass transport and increased ionic conductivity. The electrode exhibits high electrocatalytic effects towards hydrazine and ascorbic acid. It is very stable against repetitive cycling in the applied potential window. 相似文献
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Ryan P. Jansonius Phil A. Schauer David J. Dvorak Benjamin P. MacLeod David K. Fork Curtis P. Berlinguette 《Angewandte Chemie (International ed. in English)》2020,59(29):12192-12198
Strain engineering can increase the activity and selectivity of an electrocatalyst. Tensile strain is known to improve the electrocatalytic activity of palladium electrodes for reduction of carbon dioxide or dioxygen, but determining how strain affects the hydrogen evolution reaction (HER) is complicated by the fact that palladium absorbs hydrogen concurrently with HER. We report here a custom electrochemical cell, which applies tensile strain to a flexible working electrode, that enabled us to resolve how tensile strain affects hydrogen absorption and HER activity for a thin film palladium electrocatalyst. When the electrodes were subjected to mechanically‐applied tensile strain, the amount of hydrogen that absorbed into the palladium decreased, and HER electrocatalytic activity increased. This study showcases how strain can be used to modulate the hydrogen absorption capacity and HER activity of palladium. 相似文献
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Pd nanoparticle/Ti electrodes are prepared by electroless plating of palladium on titanium plates. The morphology and surface analysis of Pd nanoparticle/Ti electrodes are investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The results indicate that palladium nanoparticles are homogeneously deposited on the surface of titanium plates. The electro-catalytic activity of Pd nanoparticle/Ti electrodes in the methanol electro-oxidation is studied by cyclic voltammetry and chronoamperometry methods. The results show that the electro-catalytic oxidation of methanol on the Pd nanoparticle/Ti electrode improved compare to pure palladium electrode and confirmed the better electro-catalytic activity and stability of these new electrodes. 相似文献
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Palladium nanoparticle decorated carbon ionic liquid electrode for highly efficient electrocatalytic oxidation and determination of hydrazine 总被引:1,自引:0,他引:1
In this work arrays of palladium nanoparticles were synthesized on carbon ionic liquid electrode (CILE) (Pd/CILE), and the electrocatalytic oxidation of hydrazine was investigated using this electrode. Electrochemical oxidation of hydrazine in phosphate buffer (pH 7) was performed using cyclic voltammetry and square wave voltammetric techniques (SWV). Using the proposed electrode, a highly reproducible and well-defined peak was obtained for hydrazine at a very low potential of −0.02 V versus Ag/AgCl. A linear dynamic range of 5-800 μM with an experimental detection limit of 0.82 μM was obtained. These results show that the proposed electrode displays better electrocatalytic activity compared to the previously reported palladium modified electrodes towards oxidation of hydrazine. 相似文献
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Surfactant-doped electrodes, palladium/polymeric pyrrole-sodium dodecyl sulfate/foam-nickel (Pd/PPy-SDS/foam-Ni) electrode and palladium/polymeric pyrrole-cetyl trimethyl ammonium bromide/foam-nickel (Pd/PPy-CTAB/foam-Ni) electrode, were prepared by electrochemical deposition method. The characteristics of the prepared electrodes were investigated. Based on the results of scanning electron microscope, X-ray diffraction, inductively coupled plasma-atomic emission spectrometry, and cyclic voltammetry tests, both of the two surfactants could improve the electrodes' electrocatalytic activity. Results also indicate that Pd/PPy-SDS/foam-Ni electrode has higher catalytic potential capability than Pd/PPy-CTAB/foam-Ni electrode. 相似文献
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The electrocatalytic oxidation of methanol has been investigated on platinium+palladium alloy electrodes of different compositions in acid, neutral and alkaline aqueous solutions.The surface characteristics (composition and roughness factor) of the alloys and the stability of the electrodes in contact with different electrolytic solutions have been studied using cyclic voltammetry. In particular, a surface enrichment in platinum due to a preferential dissolution of palladium and an increase of the roughness factor with an increase of the palladium content has been shown.The electrocatalytic activity of different alloys for methanol oxidation has been characterized by exchange current densities obtained from extrapolation of Tafel lines of calculated equilibrium potential. The plot of these current densities vs. the surface composition leads to a synergistic effect, particularly important in alkaline medium. A reasonable explanation of this enhanced electroactivity at about 15 at.% in Pd is given on the basis of a decrease of electrode poisoning. 相似文献
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Cun Zhong ZHANG Jing YANG Zhong Da WU* Sheng Min CAI En Qin GAO Department of Chemistry Beijing Normal University Beijing Department of Chemistry Peking University Beijing 《中国化学快报》2001,(1)
Many methods have been adopted to improve the character of photo-electrochemistry of TiO21,2. Ion implantation is a technique with unique advantage to modify other electrodes and has been used in many electrochemical research fields3. In this paper we chose palladium ion implantation to modify nano-crystallineTiO2 and investigated the effect of implanted Pd. ExperimentalThe nano-crystalline TiO2 was prepared with hydrothermal method which was reported elsewhere4. The pH of reaction media w… 相似文献
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Mirghasem Hosseini Mohamad Mohsen Momeni 《Journal of Solid State Electrochemistry》2010,14(6):1109-1115
Au/TiO2/Ti electrode was prepared by a two-step process of anodic oxidation of titanium followed by cathodic electrodeposition of
gold on resulted TiO2. The morphology and surface analysis of Au/TiO2/Ti electrodes was investigated using scanning electron microscopy and EDAX, respectively. The results indicated that gold
particles were homogeneously deposited on the surface of TiO2 nanotubes. The nanotubular TiO2 layers consist of individual tubes of about 60–90 nm in diameter, and the electrode surface was covered by gold particles
with a diameter of about 100–200 nm which are distributed evenly on the titanium dioxide nanotubes. This nanotubular TiO2 support provides a high surface area and therefore enhances the electrocatalytic activity of Au/TiO2/Ti electrode. The electrocatalytic behavior of Au/TiO2/Ti electrodes in the glucose electro-oxidation was studied by cyclic voltammetry. The results showed that Au/TiO2/Ti electrodes exhibit a considerably higher electrocatalytic activity toward the glucose oxidation than that of gold electrode. 相似文献
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Different ways of making pH-sensing electrodes from monocrystalline or polycrystalline antimony, iridium and palladium have been investigated. Monocrystalline antimony and iridium are superior to the polycrystalline elements with respect to reproducibility between electrodes and stability of the electrode potential over long periods of time. No good palladium/palladium oxide electrode could be obtained by electrochemical oxidation and the thermal preparation method could not take advantage of the properties of the monocrystalline palladium. Therefore, only polycrystalline palladium was used to study this type of electrodes. The different electrodes were compared with respect to the manner of preparation, the pH-response (reproducibility and time response) and the effect that different complexing ligands present in the measuring solutions may have on the electrode response. Also, the redox-response of the electrodes and the effect of different oxygen pressures on the electrode potentials were studied. The monocrystalline antimony electrodes have the best reproducibility and long-term stability but also respond to complexing ligands and to variations in the oxygen pressure. Monocrystalline iridium electrodes can be obtained by continuously cycling the potential between -0.25 and +1.25 V (SCE) in 0.5M sulphuric acid. They do not respond to the complexing ligands tested, and have fairly good long-term stability, but the reproducibility between electrodes is inferior to that of the monocrystalline antimony electrodes. Polycrystalline antimony and iridium electrodes were inferior to the monocrystalline ones. The properties of the palladium electrodes were similar to those of the iridium ones. 相似文献