Poly(1-amino-9,10-anthraquinone-co-o-phenylenediamine) (P1AAQ-co-POPD) was synthesized by electrochemical methods on stainless steel electrodes (SS) using equal monomer concentration in acetonitrile/acidified water mixture as solvent. Electrochemical characterization allows, among others, determining the characteristic redox couple potential of the quinone group, which is one of the advantages of having achieved the copolymerization. FT-Raman, ATR and UV-Vis characterization confirms the formation of the copolymer, particularly, by the occurrence of a novel signal ascribed to a new C-N type bond. Besides, the conductivity of the deposits was determined, which enabled the conducting properties of the products to be verified. The topographical and morphological characterization accomplished by atomic force (AFM) and transmission electron (TEM) microscopy showed how the inclusion of o-phenylenediamine (OPD) increases the homogeneity of the copolymer, which in turn enables designing likely applications of the electrode modified with this novel polymeric material.
One-dimensional electrochemical cellular automaton (1D-ECA) has been extended so that the boundary, or electrode, can act as a catalyst, allowing for intermediate short-lived adsorbates to be transformed to and from the chemical species existing in the adjacent region within the electrolytic solution. Cyclic voltammograms have been calculated for typical sets of parameter values corresponding to fast surface reactions.
Co/Cu multilayers were electrodeposited on a brass substrate with a target layer thickness of 4 nm in a single electrolyte, and their magnetic properties and microstructure were investigated. Cross sections of the samples were observed using field-emission scanning electron microscopy, and electron backscatter diffraction measurements were also conducted. Each sample was composed of columnar crystal grains vertical to the substrate, with each grain having a Co/Cu multilayered structure. During growth of the grains, the layers were bent regularly at specific boundary lines in the cross section and were thus composed of a zigzag multilayered structure. The magnetic properties were measured using a vibrating sample magnetometer. The saturation magnetization and residual magnetization of Co in the sample were close to those for a 500-nm-thick Co layer, whereas the coercivity was significantly larger. The mechanism responsible for this coercivity increase was partly determined to be topological coupling among the Co layers which are single domain and have in-plain magnetic anisotropy.
We synthesized Li(Mn, M)0.5(Ni, M′)0.5O2 (M = Al, Ti; M′ = Mg) by a conventional solid-state method, and investigated their electrochemical properties, crystal and electronic structures. From X-ray diffraction patterns, it was found that the synthesized samples had a single phase of the layered rock-salt structure. In addition, it was demonstrated by metal composition and valence analyses that the oxygen tended to be deficit slightly in the Al- and Mg-substituted samples. Charge-discharge cycle tests indicated that the samples exhibited different cathode performance depending on substitution; that is, the Ti-substituted samples exhibited better cycle performance than LiMn0.5Ni0.5O2, and Al and Mg substitutions deteriorated the cathode property. In order to study the substitution effects on their crystal structures, the Rietveld analysis using neutron diffractions was carried out. As a result, it was found that the Ti substitution made the structure distortion smaller. This may be one of the reasons why the Ti substitution improved the cathode properties of LiMn0.5Ni0.5O2.
Diamond-like carbon (DLC) films were deposited on Mg substrate in CH3OH and KNO3 solution by the liquid-phase electrodeposition technique at ambient pressure and temperature. The applied voltage between the electrodes was low (130 V) due to the use of conductive inorganic liquids. The surface morphology was examined by Scanning Electron Microscopy (SEM). Corrosion performance of the films was investigated by potentiodynamic polararization tests and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The structure of the films was characterized by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman spectroscopy analysis of the films revealed two broad bands at approximately 1369.5 and 1554.7 cm−1, relating to D and G-band of typical DLC film, respectively. The low intensity ratio of ID/IG indicate that the DLC films have a high ratio of sp3 to sp2 bonding, which is also in accordance with the results of XPS spectra. SEM showed that DLC film was uniform, homogeneous but rough. Potentiodynamic polarization curve and EIS indicated the corrosion resistance of the Mg substrate was markedly improved by DLC films. A mechanism for the formation of sp3 and sp2 hybridizations is proposed.
Biofuel cell is a next-generation energy device that generates the electricity from renewable fuels such as glucose using redox enzymes as electrode catalyses. We re-constructed in vitro pentose phosphate pathway for 24-e oxidation of glucose-6-phosphate (G6P) into CO2 and linked it to mediated bioelectrocatalytic NADPH oxidation system in order to improve the energy density of biofuel cells. The electrolysis efficiency reached to 40% in the G6P oxidation by adjusting the composition of the enzymes in the pathway.