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Glycerol oxidation is studied at Pd nanoparticles (NPs) obtained by electroless metal deposition on PEDOT-coated graphite electrodes. Pre-reduced PEDOT coatings with different polymerization charges and different doping ions (polystyrenesulfonate, PSS or dodecyl sulfate, SDS) are used to drive the electroless deposition of Pd NPs. Pd nanocatalysts with metal loadings in the order of 15–30 μgcm−2 and high electroactive surface area (EASA) are obtained. Oxidation of glycerol is studied in dependence of the type of doping (PSS or SDS) and polymerization charge. It is found that at constant Pd loading PEDOT/PSS-supported catalysts have a three times higher glycerol peak oxidation currents. The mass activity (MA) diminishes with increasing Pd loading on both types of PEDOT but for different reasons. Impeded access of glycerol to NPs deposited deeply in the polymer structure is suggested for the porous and hydrophilic structure of PEDOT/PSS. Aggregation of NPs and therefore smaller EASA due to the upper surface confined metal deposition process are operative at PEDOT/SDS coatings. These are also the reasons for the low MA values observed on this type of PEDOT support. MA values at PEDOT/PSS-coated graphite are found to range between 1100 and 1200 mAmg−1 and are between the best values obtained on Pd-supported catalysts. [ABSTRACT FROM AUTHOR]

Pd electroless deposition is carried out at the expense of oxidation of pre-reduced poly(3,4-ethylene dioxythiophene) (PEDOT)-coated electrodes. Two largely differing potentials for deep and mild pre-reduction of PEDOT are chosen and correspond to initial low (deep pre-reduction) and, correspondingly, high (mild pre-reduction) conductive states of the polymer material. The role of organic doping ions (polysterene sulfonate, PSS or dodecyl sulfate, SDS) used in the course of PEDOT synthesis for the electroless deposition of Pd is also investigated. PEDOT-supported Pd catalysts with high-density homogeneous distribution of Pd nanoparticles (NPs) with sizes ranging between 4 and 12 nm are obtained. The amount of deposited metal depends significantly on the pre-reduction potential of PEDOT whereas the surface density of the metal NPs is largely influenced by the doping ions used to obtain the PEDOT material. Evidence for irreversible structural transformation obtained upon deep pre-reduction of PEDOT:SDS is obtained. [ABSTRACT FROM AUTHOR]

On 2003 August 14, a M w = 6.2 earthquake occurred offshore the Lefkada Island in the eastern Ionian Sea, one of the most seismically active areas in Europe. The earthquake caused extended damages in the island, and a number of ground failures, especially along the north-western coast. Seven ascending ENVISAT/ASAR images are used to process six co-seismic interferograms. The ROI-PAC package is used for interferogram generation with the SRTM DEM applied in a two-pass method. The formation of the co-seismic pairs is limited due to the existence of one pre-seismic image only. Dense vegetation is covering the island, which is an obstacle in getting good coherence, since C-band images are used. Nevertheless, ground deformation, of > 56 mm (two fringes) in the line of sight of the satellite, is detected in all six co-seismic interferograms. By inversion of the data from the observed fringes, a best fitting model of the activated fault is calculated assuming a dislocation in an elastic half space. The inferred fault is a pure dextral strike-slip fault, dipping 59 ± 5° eastward, 16 ± 2 km long and 10 ± 2 km wide. It is located north of the fault of the M w = 6.5 2015 November 17 earthquake, and a 10–15 km gap remains between the two faults. The 2003 fault does not reach the surface and its upper edge is at a depth of 3.5 ± 1 km. No evidence is found of slip south of the Lefkada Island as suggested by some seismological studies. [ABSTRACT FROM AUTHOR]

Abstract: Bi-metal modification of poly-3,4-ethylenedioxythiophene (PEDOT) layers by combining palladium and copper deposition is studied. Initial reference measurements are performed on electrodriven deposition and electroless precipitation of palladium, showing the existence of Pd nanocrystals on the PEDOT surface. It is established that by using the electrodeposition sequence – Cu (first step) – Pd (second step) only palladium remains available in the PEDOT layer. By reversing the deposition sequence – Pd (first step) – Cu (second step) a bi-metal modification of PEDOT is achieved. Depending on the parameters potential and time of the copper electroreduction the Pd nanocrystals coexist with either Cu–PEDOT-stabilized species or both Cu crystals and Cu–PEDOT-stabilized species. The voltammetric response of the modified PEDOT electrodes is tested for nitrate electroreduction in neutral solution. It is found that the bi-metal modified PEDOT shows a marked electroactivity for this reaction. [Copyright &y& Elsevier]

Abstract: Electrochemical reduction of copper ions in poly(3,4-ethylenedioxythiophene) (PEDOT), performed at low overpotential or low current density, allows for stabilization of Cu(I) species in the polymer layer. The electrocrystallization of copper at high overpotential is explored in absence and presence of pre-stabilized Cu(I) species in PEDOT. It is found that the copper–pre-stabilized material allows for a five-fold increase of the number of deposited copper crystals. Statistical analysis of the distances between neighbouring crystals shows for both (as-synthesized and copper–pre-stabilized) materials a significant deviation from random Poisson probability distribution. For the first time, the experimental distributions are fitted by a theoretical probability model, accounting for the finite size of the crystals. The statistical analysis allows excluding the role of zones of reduced overpotential in the nucleation stage of electrocrystallization and concluding that new sites for nucleation become active in the presence of Cu(I)-stabilized species in PEDOT. [Copyright &y& Elsevier]

Palladium (Pd) nanocatalysts are obtained by electroless deposition of Pd on pre-reduced poly(3,4-ethylenedioxythiophene) (PEDOT) layers doped with either polystyrenesulfonate (PSS) or dodecylsulfate (SDS) ions. The PEDOT-supported Pd catalysts are investigated with respect to formic acid (FA) oxidation in slightly acidic solution under voltammetric and chronoamperometric conditions. Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) studies are carried out before and after exposure to FA. It is established that the dopant used for the synthesis of PEDOT does affect not only the distribution of the Pd nanoparticles on the polymer surface but also the stability of the composites upon electrochemical treatment in the presence of FA. It is found that PEDOT-PSS undergoes structural rearrangement, and significant loss of the Pd catalyst is observed. In comparison, PEDOT-SDS is more resistant to FA exposure since aggregated Pd nanoparticles are providing additional stability of the polymer structure. [ABSTRACT FROM AUTHOR]

Abstract: Selection of stable Lavandula vera MM cell lines producing high amounts of rosmarinic acid (RA) was performed using m-F-d,l-phenylalanine and p-F-d,l-phenylalanine. As a result, two callus lines L. vera MF and L. vera PF were obtained, which produced 1.95 and 1.71 times more rosmarinic acid in comparison with the parent culture. After adaptation of the selected callus lines in liquid media the achieved yields of rosmarinic acid were 2808.4mgL−1 (in L. vera MF cell suspension) and 2594.6mgL−1 (in L. vera PF cell suspension). [Copyright &y& Elsevier]