Journal of Solid State Electrochemistry

Holze, Rudolf

doi: 10.1007/s10008-006-0211-2pmid: N/A

Yevtushenko, O.; Natter, H.; Hempelmann, R.

doi: 10.1007/s10008-006-0212-1pmid: N/A

Nanocrystalline gold is electrodeposited from a stable nontoxic bath, in which Au+ is stabilized by complex formation with 3-mercapto-1-propanesulfonic acid sodium salt. Nanoscaling is achieved by pulse techniques. The crystallite size is strongly dependent on physical and chemical process parameters, such as pulse duration, current density, bath temperature, type, and amount of additives; especially, we observe a decrease of the crystallite size down to 16 nm by the proper choice of current density and temperature, and down to 7 nm by the use of additives. The thermal stability of nanocrystalline gold is investigated by in situ high-temperature X-ray diffraction; nanogold exhibits a thermal stability up to 673 K. An activation energy of 37 kJ mol−1 is determined for the grain-growth kinetics.

Gajdzik, J.; Szamocki, R.; Natter, H.; Kohring, G.; Giffhorn, F.; Hempelmann, R.

doi: 10.1007/s10008-006-0213-0pmid: N/A

Sorbitol dehydrogenase (SDH) originating from recombinant Escherichia coli cells is immobilized on gold electrodes. First of all, (4-carboxy-2,5,7-trinitrofluorenyliden)malon-nitrile (CTFM) is adsorbed on the surface as mediator. In a second step, the cofactor β-nicotinamide adenine dinucleotide (NAD+) is immobilized on the gold electrode. Due to the formation of a complex between the mediator and the cofactor, the electron transfer rate can be enhanced by adding calcium ions to the buffer. The immobilization of NAD+ and SDH on the surface has been achieved by cross-linking with the glutaraldehyde/bovine serum albumin system. The successful biofunctionalization is monitored by cyclic voltammetry.

Yang, Yongan; Bittner, Alexander; Kern, Klaus

doi: 10.1007/s10008-006-0214-zpmid: N/A

We report surface-enhanced Raman scattering (SERS) from a “sandwich” structure of two silver layers, in which a thin film of activated carbon is embedded. The first silver layer is prepared by electroless deposition on a non-conductive substrate, while the second one is electrodeposited on the adsorbed carbon powder. This “sandwich” does not only yield stable SERS signals from the carbon but also a strong additional enhancement (compared to SERS from simple carbon/silver or silver/carbon structures), stemming from a coupling of the two silver layers. The “sandwich” structure should be widely applicable since its preparation is very simple.

Tittes, Kerstin; Plieth, Waldfried

doi: 10.1007/s10008-006-0217-9pmid: N/A

Alkaline solution, especially diphosphate solutions, can be used as electrolytes for the galvanic deposition of p-type semiconductors. A ternary Bi–Sb–Te alloy semiconductor was deposited at a Ni-covered cathode surface at potentials lower than −0.6 V (Ag/AgCl), under potentiostatic condition in well-stirred solutions. Additionally, it was possible to deposit antimony telluride, a binary p-semiconductor, from the ternary electrolyte. The kinetics of the process was investigated by cyclic voltammetric measurements. The influence of the electrolyte convection on the electrocrystallization was analysed with the help of rotating disc electrode. The semiconductor layers were characterized by electrochemical impedance spectroscopy.

Patra, Chitta; Odani, Ayelet; Pol, Vilas; Aurbach, Doron; Gedanken, Aharon

doi: 10.1007/s10008-005-0086-7pmid: N/A

A novel and quick method has been developed for the preparation of tin sulfide (SnS and SnS2) nanoflakes in high yield (≈93%) by a microwave irradiation technique for 10–40 min. The sulfides were synthesized in a simple domestic microwave oven (DMO) using stannic chloride and stanous chloride as the precursors of tin and thiourea as the precursor of sulfur in ethylene glycol under argon atmosphere. Elemental sulfur and sodium thiosulfate were also tried as precursors of sulfur. The structures, morphologies, compositions, and physical properties of the products were characterized by powder X-ray diffraction (XRD), differential scanning calorimetry, energy dispersive X-ray analysis, transmission electron microscopy, selected area electron diffraction, Raman spectroscopy, and standard electrochemical techniques. The XRD patterns indicate that the as-synthesized product, obtained after microwave irradiation, is crystalline orthorhombic in the case of the SnS phase and amorphous in the case of SnS2. Heat treatment of this SnS2 produced a crystalline hexagonal phase. A possible mechanism for the formation of the tin sulfide nanoflakes is proposed herein. The electrochemical performance of these materials as Li-insertion materials was investigated in a number of electrolyte solutions and was found to be highly sensitive to the solution composition. A stable reversible capacity higher than 600 mAh/g could be obtained with SnS electrodes.

Zong, H.; Cong, C.; Wang, L.; Guo, G.; Liu, Q.; Zhang, K.

doi: 10.1007/s10008-005-0087-6pmid: N/A

Yttrium-doped lithium manganese oxide (LiMn0.98Y0.02O2) was prepared by ion exchange of lithium for sodium in NaMn0.98Y0.02O2 precursors obtained by using rheological phase reaction method. This material had small particle size, which was composed of grain size of about 100 nm. Especially, LiMn0.98Y0.02O2 delivered the initial discharge capacity of about 191 mA h g−1 at room temperature when cycled between 2.0 and 4.4 V vs Li/Li+. Moreover, it showed an excellent cycling behavior, its specific capacity remained above 173 mA h g−1 after 20 cycles, and the material did not transform into spinel structure during the electrochemical cycling according to the cyclic voltammograms and X-ray powder diffraction. The electrochemical results revealed that the doping of Y3+ improved the performance of LiMnO2 considerably.

Shibli, S.; Dilimon, V.; Saji, V.

doi: 10.1007/s10008-005-0088-5pmid: N/A

It has been recently proved that RuO2 can act as an effective surface activator of aluminum alloy sacrificial anodes. TiO2 has the property of stabilizing RuO2 coating and resisting biofouling on metal surfaces. Hence, a mixed oxide catalytic coating of TiO2 and RuO2 can enhance the galvanic performance of aluminum alloy sacrificial anodes and resists biofouling on the anode surface. In the present work RuO2–TiO2 mixed oxide was coated on aluminum alloy sacrificial anodes. The large and uniform porous nature of the coating was found to facilitate efficient ion diffusion. The coating was found to persist on the anode even after 3 months of galvanic exposure. The anode having an optimum combination of the mixed oxide had 70% TiO2 as the major component in the coating. The catalytic coating significantly improved the performance of the anodes to a large extent.

Arsova, Irena; Arsov, Ljubomir; Hebestreit, Niels; Anders, Andreas; Plieth, Waldfried

doi: 10.1007/s10008-005-0089-4pmid: N/A

Electrochemical formation of anodic oxide films on niobium (Nb) surfaces in 1 M H2SO4 solutions was studied using ellipsometry and Raman spectroscopy. By in situ ellipsometric measurements, the coefficient of film thickness growth and the complex index of refraction of anodic oxide films in the voltage range between 0 and 100 V were determined. The Raman spectra reveal that the thin passive films are amorphous. In the beginning of crystallization, the anodic oxide films consist of mixtures of NbO2 and Nb2O5, while NbO2 is completely transformed to Nb2O5 for thicker and well-crystallized films.

Bhattacharya, Chinmoy; Datta, Jayati

doi: 10.1007/s10008-005-0091-xpmid: N/A

In the present investigation, polycrystalline semiconductor Cd–Se–Te films have been electrodeposited at room temperature on conducting glass substrates using cyclic voltammetric technique under controlled periodic scans. The successive anodic and cathodic scans were recorded within the potential range, from 0 to −1.0 V, and over the range of periodic cycles, from 250 to 2,000, in an acidic bath containing respective reducible precursor ions like Cd2+, Se4+, Te4+, and 1 vol.% Triton X-100 as the surface-active reagent. Thin composite films were produced having variable thickness and composition and grain size of the order of 80–100 nm. The film properties were determined by focused ion beam analysis, energy dispersive analysis of x-rays, x-ray diffraction studies, atomic force microscopy, and scanning electron microscopy. Thickness of the semiconductor films was found to increase linearly with the number of voltammetric cycles. Band gap energies of the films as derived from the reflectance spectra were found to lie between 1.4 and 1.7 eV. The composite films of the Cd–Se–Te ternary system when electrochemically characterized in aqueous polysulfide solution exhibited n-type semiconducting properties and photoconversion efficiency more than 0.4%.