Electrodeposition of mesoporous ruthenium oxide using an aqueous mixture of CTAB and SDS as a templating agent

Mesoporous RuO₂ films were electrochemically fabricated on ITO-coated glass substrate from aqueous ruthenium chloride (RuCl₃·nH₂O) solution. To achieve highly stable mesoporous structure, an aqueous mixture of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) was used as a templating agent.The mesoporous structure was confirmed by small angle X-ray diffraction (SAXRD) and transmission electron microscopy (TEM). The addition of small amount (10wt%) of CTAB significantly improved the stability of porous structure. The crystallinity of synthesized RuO₂ thin film was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Specific capacitance of the synthesized films was evaluated by measuring cyclic voltammetry (CV) and charge-discharge curves in 0.5 M H₂SO₄. Compared with non-porous electrode, mesoporous RuO₂ showed higher supercapacitor performance.     

Fast and selective Cu2O nanorod growth into anodic alumina templates via electrodeposition

The fast and selective growth of cuprous oxide (Cu₂O) nanorods into anodic aluminum oxide (AAO) templates is achieved under optimized alkaline conditions via electrochemical deposition. The growth rate of Cu₂O nanorods at room temperature reached 360 nm/min, the fastest rate reported to date. The synthesis of Cu₂O nanorods by applying a constant current by using Cu₂O nanotubes as a transition state is extensively discussed; a Pt pottery-shaped layer played a key role as a seed layer for the fast Cu₂O growth. We report here the existence of regions of nanostructured Cu₂O based on our studies and previous relevant works, which include potential-pH curves for Cu²⁺-lactate solutions.     

The key factors in fabrication of high-quality ordered macroporous copper film

The template-directed fabrication of highly-ordered porous film is of significant importance in implementation of the photonic band gap structure. The paper reports a simple and effective method to improve the electrodeposition of metal porous film by utilizing highly-ordered polystyrene spheres (PSs) template. By surface-modification method, the hydrophobic property of the PSs template surfaces was changed into hydrophilic one. It was demonstrated that the surface modification process enhanced the permeability of the electrolyte solution in the nanometer-sized voids of the colloidal template. The homogeneously deposited copper film with the highly-ordered voids in size of less than 500 nm was successfully obtained. In addition, it was found that large defects, such as microcracks in the template, strongly influenced the macroporous films quality. An obvious preferential growth in the cracked area was observed.     

钼镍镀层的制备及其光谱性能（英文）

采用电沉积法在镍合金表面制备钼镍镀层。研究钼镍镀层的硬度、磨损质量和摩擦系数、热膨胀等性能。分别用发射光谱法、能谱法、扫描电镜法和X衍射法等对钼镍镀层进行表征。在镍合金表面镀上一层钼镍镀层,可使其的硬度和耐磨性大幅度提高并减小磨擦系数,钼镍镀层的硬度为518 HV,比镍合金的硬度(300 HV)提高了72.67%;钼镍镀层的磨损质量是镍合金的磨损质量的1/1.94;镍合金和钼镍镀层的磨擦系数分别为0.640和0.559。镍合金的物理热膨胀曲线在100~120℃温度范围和570~640℃范围形成了2个峰,镍合金+钼镍镀层的物理热膨胀曲线在570~640℃范围形成了1个峰。在570~640℃范围可明显改善其热膨胀,镍合金+钼镍镀层的物理热膨胀曲线在570~640℃范围形成的峰远比镍合金的物理热膨胀曲线在570~640℃范围形成的峰小,可能是因为钼进入到镍的晶格中,抑制了镍在570~640℃范围发生晶格转变(bcc→fcc)所致。镍合金+钼镍镀层的物理热膨胀曲线在595~625℃范围形成的小峰,可能是由于MoNi_4和MoNi由半晶型结构转变为晶型结构所致。     

Structural and electrical studies of template synthesized copper nanowires

The template strategy combined with electrodeposition technique has been used to produce copper nanowires in the cylindrical pores of track-etched polycarbonate membranes. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–visible spectroscopy have been used to characterize as-prepared copper nanowires. XRD study shows the face centered cubic crystal structure of copper nanowires. Williamson–Hall (WH) analysis has been used to determine the crystallite size and microstrain induced due to lattice deformation. FESEM results reveal that copper nanowires are continuous, well aligned with uniform diameter and having high aspect ratio. The optical absorption spectra exhibit a strong peak at 568 nm attributed to the surface plasmon resonance. The current–voltage (I–V) characteristics show an ohmic behavior of the fabricated copper nanowires. The increase in resistivity of nanowires than that of bulk counterpart has been attributed to the surface and size effects in nanowires and explained in the light of Fuchs–Sondeimer and Mayadas–Shatzkes models.     

Cyclic voltammetry study of electrodeposition of CuGaSe2 thin films on ITO-glass substrates

The electrodeposition mechanism of CuGaSe₂ (CGS) thin films on ITO substrates has been investigated using cyclic voltammetry technique. The cyclic voltammetric study was performed in unitary Cu, Ga and Se systems, binary Cu–Se, Ga–Se systems and ternary Cu–Ga–Se system. The electrodeposition metallic Ga from Ga unitary electrolytes is impossible due to its low reduction potential. No reduction peak was found for the reduction of Ga³⁺ to Ga in the cyclic voltammogram of unitary system. However, in the cyclic voltammogram of ternary Cu–Ga–Se system, reduction peak at −0.6 V was observed with addition of GaCl₃. Also, current density of the peak was increased with increasing concentration of GaCl₃. It is corresponded to the formation of gallium selenides and/or copper–gallium–selenium compounds. The contents of Ga in the films were significantly changed from −0.4 V to −0.6 V. SEM and XRD analysis also showed that surface morphology and crystalline phase of films were significantly changed with increasing Ga content.     

Zinc-cobalt alloy: electrodeposition and characterization

Zinc-cobalt alloy electrodeposits offer enhanced corrosion protection to steel, compared to zinc deposits. A near neutral zinc-cobalt alloy sulfate bath was developed. In the absence of β-naphthol and sodium lauryl sulfate (SLS), only a light grey and non-uniform deposit was obtained. Addition of boric acid yielded a grey and uniform deposit. To obtain the grey uniform alloy deposit, the optimum bath composition was: 0.5 M ZnSO₄, 0.5 M CoSO₄, 40 g/L H₃BO₃, 0.865 g/L SLS and 0.345 g/L β-naphthol. The current efficiency for alloy deposition was 50% in the current density range 0.5–2.5 A/dm². X-ray fluorescence studies on the alloy deposit formed on steel revealed 58–75% zinc on the surface. Anodic stripping voltammetric studies were carried out on zinc-cobalt alloy films formed on glassy carbon to identify the phases formed in the alloy. Zn-Co alloy film dissolution peaks suggested the existence of β, β₁ and γ phases of the alloy. Electronic Publication     

电沉积制备钯铂电极上乙醇的电催化氧化

研究了乙醇在碱性介质（１．０ｍｏｌ·Ｌ－１ＮａＯＨ）中电沉积制备的Ｐｄ／ＧＣ、Ｐｔ／ＧＣ和Ｐｄ．Ｐｔ／ＧＣ电极上的电催化氧化．实验结果表明：由此法制备的钯铂系列合金电极对乙醇的电催化氧化表现出明显的协同效应─—乙醇在含把原子分数ｙｐｂ＝０．３３６的Ｐｄ－Ｐｔ／ＧＣ合金电极上的阳极交换电流密度是其在纯铂电极上的３０多倍．     

Corrosion resistance and lubricated sliding wear behaviour of novel Ni-P graded alloys as an alternative to hard Cr deposits

Alternative process to hexavalent chromium, substitute materials and new designs are urgently needed owing to the requirement of “clean” manufacture. This comparative study was conducted to systematically investigate the corrosion resistance and lubricated sliding wear behavior of graded Ni-P alloy deposits produced from a single plating bath by electrodeposition and hard Cr deposits, using potentiodynamic polarization and reciprocating ball-on-disc tribometer. Results showed that Ni-P deposits heat-treated at 400 °C with maximum hardness exhibited more than two orders of magnitude higher corrosion resistance than hard Cr deposits in 10 wt.% HCl solution. The Stribeck curves for the heat-treated Ni-P gradient deposits and hard Cr under lubrication conditions were obtained with accurate control of normal load and sliding speed during the wear process, three main different regimes corresponding to different lubrication mechanism were identified. Heat-treated Ni-P gradient deposits showed relatively poor wear resistance than hard Cr deposits under the lubrication conditions, which may be attributed to superior oil-retaining surface structure and the unique “nodular” effect of hard Cr in wear process.     

Intermediate molybdenum oxides involved in binary and ternary induced electrodeposition

The first stages of Co–Ni and Co–Ni–Mo deposition in sulphate–citrate medium at pH 4.0 were analysed. In both cases, the formation of non-hydrogenated nickel on the electrode before alloy deposition was detected by linear sweep voltammetry and inductively coupled plasma mass spectrometry. Co–Ni electrodeposition was anomalous since the Co/Ni ratio in the alloy was higher than the corresponding [Co(II)]/[Ni(II)] ratio in solution. The adsorption of Co(II) over the initial nickel could explain the anomalous codeposition, which persisted with the addition of molybdate to the Co–Ni bath. However, the formation of intermediate molybdenum oxides also took place. A mechanism has been proposed to describe the sequence of steps for Co–Ni–Mo electrodeposition. Under our conditions, the alloy is formed mainly from free Co²⁺ and Ni²⁺ cations, whereas molybdate is reduced firstly to molybdenum oxide from MoO₄(H₃Cit)²⁻ and, secondly, NiCit⁻ catalyses the subsequent reduction to molybdenum metal of the intermediate [MoO₂–NiCit⁻]_ads species.