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Thin films containing BiVO 4 and MnO 2 deposited on FTO and modified by Au nanoparticles were studied towards their photoelectrochemical and photocatalytical activities in an aqueous electrolyte. Electrodes were prepared by the pulsed laser deposition (PLD) method. The surfactant-free ablation process was used for preparation of the gold nanoparticles (GNP) water suspension. Obtained layers of varied thicknesses (27–115 nm) were characterized using Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy. Electrochemical methods such as electrochemical impedance spectroscopy, linear voltammetry and chronoamperometry under visible light illumination and in the dark were applied to characterize layers as photoanodes. Simple modification of the BiVO 4 + MnO 2 layer by drop-casting of small amount of colloidal gold (1.5 × 10 −14 mol of GNP on 1 cm 2 ) leads to enhancement of the generated photocurrent recorded at E = 0.5 V vs. Ag/AgCl (0.1 M KCl) from 63 μA/cm 2 to 280 μA/cm 2 . Photocatalytical studies were also exploited towards decomposition of methylene blue (MB). A possible mechanism of MB photodegradation was proposed. The formation of hydroxyl radicals was detected by photoluminescence spectra using terephthalic acid as the probe molecule.

The yttrium, iron and niobium doped-SrTiO 3 powders have been successfully fabricated by a modified low–temperature synthesis method from a polymer complex. The usage of strontium hydroxide precursor instead of conventional strontium nitrate or strontium carbonate provides to the possibility of significant decrease of annealing temperature. It allows to prepare a material with sphere-shape grains of nanometric size (15–70 nm). The results of thermal analysis indicate that the crystallization of precursor takes place at different stages. The product after heat treatment at 600 °C for 3 h in air was also characterized by X-Ray diffraction method (XRD) and Fourier transform – infrared spectroscopy (FT-IR). After the crystallization and the impurity removal process, a single-phase material was obtained in case of all analyzed samples. The morphology of obtained nano-powders was also studied by a scanning electron microscopy (SEM). It can be concluded, that this method allows obtaining a perovskite phase of a metal doped SrTiO 3 with nanometric particles.

In a significant amount of cases, the highly ordered TiO2 nanotube arrays grow through anodic oxidation of a titanium metal plate immersed in electrolyte containing fluoride ions. However, for some practical applications, e.g. solar cells or electrochromic windows, the semi-transparent TiO2 formed directly on the transparent, conductive substrate is very much desired. This work shows that high-quality Ti coating could be formed at room temperature using an industrial magnetron sputtering system within 50 min. Under optimized conditions, the anodization process was performed on 2 μm titanium films deposited onto the FTO (fluorine-tin-oxide) support. Depending on the electrolyte type, highly ordered tubular or porous titania layers were obtained. The fabricated samples, after their thermal annealing, were investigated using scanning electron microscopy, Raman spectroscopy and UV–vis spectroscopy in order to investigate their morphology, crystallinity and absorbance ability. The photocurrent response curves indicate that materials are resistant to the photocorrosion process and their activity is strongly connected to optical properties. The most transparent TiO2 films were fabricated when Ti was anodized in water electrolyte, whereas the highest photocurrent densities (12 μA cm−2) were registered for titania received after Ti anodization in ethylene glycol solution. The obtained results are of significant importance in the production of thin, semi-transparent titania nanostructures on a commercial scale.

New plasmonic platform was successfully obtained to investigate the increase of fluorescence intensity of a fluorophore in the presence of silver nanoparticles. A flavin mononucleotide, was selected by us as a fluorophore for this study as a very important biological compound playing a key role in many biochemical process. Plasmonic platforms were characterized by means of luminescence spectroscopy. Flavin mononucleotide deposited on plasmonic platform exhibits dramatic emission enhancements in presence of silver nanoparticles deposited on gold mirror.

The Bi Sb Te alloys with different Bi/Sb/Te ratio were fabricated by an innovative method. For that purpose the oxide reagents were melted at high temperature, then quenched to form pellets, milled to a powder and finally reduced in hydrogen at various temperatures. Complex structures consisting of connected thin layers forming a continuous path between nano- and micrometer size grains have been obtained. The electrical conductivity, Seebeck coefficient and thermal conductivity have been determined over temperature range from −196 to +300 °C in argon atmosphere. The highest figure of merit in the whole temperature range was found for Bi0.4Sb1.6Te3 compound reduced at 400 °C for 10 h in hydrogen atmosphere. At a near-room temperature the figure of merit of this compound was found to be equal to 0.7.

Widespread commercialization of solid oxide fuel cells requires lowering its cost. It is generally accepted that to lower the cost of solid oxide fuel cells it is necessary to use metal alloys as interconnectors and, consequently, lower its operating temperature to slow down interconnectors degradation. As a result the area specific resistance of the cathodes should be lowered to sustain the performance of the cells. In order to slow the interconnectors degradation (due to corrosion and interdiffusion with the anode) and improve the performance of the cathodes, novel functional layers are introduced to the structure of the fuel cells. In this paper, results related to three kinds of functional layers will be presented: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow down inter-diffusion of atoms and thin and dense interconnector coatings to slow down interconnectors degradation. The investigated layers are deposited by cost effective spin coating and spray pyrolysis methods. Introduction of the layers show positive and promising results.

The Hebb–Wagner polarization method with the electron blocking electrode has been discussed in this paper in aim to determine a partial ionic conductivity of Sr-doped lanthanum manganite. The “limiting current” in the proposed system was measured using the two-point DC technique with additional Pt electrode between LSM and blocking electrode. The electrochemical model based on bulk diffusion processes and Boltzmann statistics has been also described. The ionic conductivity calculated with the use of proposed model for La 0.7 Sr 0.3 MnO 3+ δ was 5.3×10 −4 S cm −1 at 800 °C and the activation energy of ionic conductivity was found to be (0.60±0.02) eV. This result is in agreement with previous literature reports and indicates the workability of the modified Hebb–Wagner system.

A novel method for thermoelectric materials fabrication using a reduction of oxide precursors in hydrogen was reported. On the example of Bi–Sb, Bi–Sb–Te and Te–Ag–Ge–Sb compounds it was shown that this simple and easy method is suitable for fabrication of two-, three- and even multicomponent thermoelectric materials. It allows controlling a composition, microstructure and even type a of electrical charge carriers. As a result of reduction of oxide precursors a layered structure with an average thickness of layers equal tens of nanometers was formed. At the near-room temperature the best material with a figure of merit (ZT) close to 0.4 was Bi0.8Sb1.2Te3Ox reduced at 340 °C for 10 h. At 350 °C a value of ZT = 0.8 was reached by the (GeTe)0.85(AgSbTe2)0.15 (TAGS85) sample reduced twice at 400 °C for 10 h.

A poly(3,4-ethylenedioxythiophene) conducting polymer doped with poly(2-styrene sulfonate) (pEDOT:PSS) was efficiently electrodeposited on a layer composed of ordered titania nanotubes.

In this paper, V2O5 nanostructures with a size depending on the annealing temperature are successfully synthesized by a sol–gel method. The crystal structure and morphology of the samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SEAD) and scanning electron microscopy (SEM), respectively. Electrochemical testing such as discharge–charge cycling (CD) and cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are employed in evaluating their electrochemical properties as cathode materials for lithium ion batteries. One-dimensional nanostructures are successfully synthesized with the same structure, composition and similar shape. The results reveal that for one-dimensional nanostructures, next to the thickness which must be as small as possible, the length of the nanocrystals is crucial and should be above 2 μm. The longer nanostructures obtained at 650 °C deliver a discharge specific capacity of 281 mA h g−1 at a current rate of C/5 which is over 95.5% of the theoretical capacity for two Li+ ion intercalation (294 mA h g−1) within a voltage window of 2.0–4.0 V.

The production and properties of the indium-tin-oxide (ITO) electrodes functionalized by Au nanoparticle (NP) arrays of a relatively large area formed by pulsed laser nanostructuring of thin gold films are reported and discussed. The SEM inspection of modified electrodes reveals the presence of the nearly spherical and disc-shaped particles of dimensions in the range of 40–120 nm. The NP-array geometry can be controlled by selection of the laser processing conditions. It is shown that particle size and packing density of the array are important factors which determine the electrode performance. In the case of NP-modified electrodes the peak current corresponding to the glucose direct oxidation process shows rise with increasing glucose concentration markedly higher comparing to the reference Au disc electrode. The detection limit reaches 12 μM and linear response of the sensor is observed from 0.1 to 47 mM that covers the normal physiological range of the blood sugar detection.

The topography, microstructure, and electrical properties of strontium–borate glass and SBO glass containing bismuth and vanadium oxides, were studied. The structure was measured using X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), and scanning electron microscope (SEM) methods. The A.C. complex conductivity was investigated as a function of temperature and frequency. The influence of the quantity of bismuth and vanadium oxides present, on glasses microstructure and electrical properties, was discussed. In order to obtain glass-ceramics, the glasses were subjected to crystallization at temperatures close to the exothermic processes indicated by the differential scanning calorimetry (DSC) measurements. X-ray diffraction (XRD) measurements were carried out to determine the presence of bismuth vanadate (Bi 2 VO 5.5 ) crystalline phase in heat-treated samples. After heat treatment, there were still some traces of the glassy phase within the samples. The effect of the crystallization process on the microstructure, topography, and dielectric behavior of the material was analyzed. The A.C. dielectric permittivity, conductivity, and impedance were discussed at specific temperature and frequency region; in addition, conduction mechanisms were proposed.

This paper reports a novel method of boron doped titania nanotube arrays preparation by electrochemical anodization in electrolyte containing boron precursor – boron trifluoride diethyl etherate (BF 3 C 4 H 10 O), simultaneously acting as an anodizing agent. A pure, ordered TiO 2 nanotubes array, as a reference sample, was also prepared in solution containing a standard etching compound: ammonium fluoride. The doped and pure titania were characterized by scanning electron microscopy, UV–vis spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, photoluminescence emission spectroscopy and by means of electrochemical methods. The B-doping decidedly shifts the absorption edge of TiO 2 nanotubes towards the visible light region and significantly inhibits the radiative recombination processes. Despite the fact that the doped sample is characterized by 4.6 lower real surface area when compared to pure titania, it leads to the decomposition of methylene blue in 93%, that is over 2.3 times higher than the degradation efficiency exhibited by the undoped material. The formation rate of hydroxyl radicals ( OH) upon illumination significantly favours boron doped titania as a photocatalytic material. Moreover, the simple doping of TiO 2 nanotubes array results in the enhancement of generated photocurrent from 120 μA/cm 2 to 350 μA/cm 2 registered for undoped and doped electrode, respectively.

Non-enzymatic glucose sensors are prominent alternatives to the commercially available glucometers. Their main advantages over enzyme–based devices are higher stability to changes of the environment such as pH and temperature and lack of complicated immobilization procedure [1]. However non-enzymatic glucose sensitive materials are typically less selective, so there is a strong requirement for the development of proper coatings or membranes in order to minimize the negative influence of interferences. Therefore we present Au-Ti heterostructure covered with various coatings (e.g. Nafion, poly(sulfobetaine methacrylate)) and novel approach for analysis of interfering species influence onto electrode performance in neutral solution. Fabrication procedure of material consists of the following steps: preparing structured titanium template (TiND) by anodization and etching of nanotubes, gold sputtering and subsequent dewetting. After those steps electrode morphology is investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) [2] revealing the presence of gold nanoparticles (AuNPs) in every dimple of Ti foil. Lastly, as formed material is covered by protective coating. Electrochemical properties and catalytic activity towards glucose oxidation are determined by standard techniques - cyclic voltammetry (CV) and impedance spectroscopy (EIS). Examining interference phenomena of various compounds (such as ascorbic acid (AA), acetaminophen (AAp), urea and glycine) is realized by both CV and EIS techniques in certain configuration. Moreover influence of those species on the catalytic activity of the material is established. Obtained results confirm the possibility of using prepared electrodes in sensors applied for noninvasive glucose detection in human body fluids. Acknowledgements This work has been financed by National Center for Research and Development under the LIDER program (LIDER/2/0003/L-8/16/NCBR/2017). References [1] Hwang, Dae-Woong, et al. "Recent advances in electrochemical non-enzymatic glucose sensors–a review." Analytica chimica acta 1033 (2018): 1-34. [2] Olejnik, Adrian, et al. "A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures." Electroanalysis 32.2 (2020): 323-332. Figure 1

Au-Cu nanostructures offer unique optical and catalytic properties unlike the monometallic ones resulting from the specific interaction. Among others, they have the ability to exhibit surface plasmon resonance, electrochemical activity towards the oxygen and hydrogen evolution reaction (OER, HER) as well as improved photoresponse in relation to monometalic but those properties depend highly on the substrate where bimetallic structures are immobilized. In this work, bimetallic gold-copper mosaics over the conducting structured titanium substrate were fabricated via following steps: anodization of Ti foil, chemical etching of as-formed titania resulting in nanodimpled Ti substrate (TiND), sputtering of thin metal layer (Au, Cu) in various sequences, and finally thermal treatment in furnace at 450 °C or 600 °C. The morphology, optical and structural properties were investigated in details and it was shown that both arrangements of metallic films and thermal conditions strongly affect the morphology and optical features. The XPS results confirmed the presence of gold-copper alloys and copper oxide species. Last but not least, the electrochemical activities were verified in 0.1 M NaOH using cyclic voltammetry and linear voltammetry measurements performed in dark and under visible light illumination. Among all investigated materials in both anodic and cathodic regimes bimetallic 5Au/5Cu sample annealed at 450 °C exhibits the highest response towards OER and HER, respectively. This is further boosted by the light with λ > 420 nm. Upon exposure to visible light, the current density for 5Au/5Cu and 5Cu/5Au electrodes reached 1.32 mA cm−2 and 1.26 mA cm−2, respectively, while in the case of monometallic structures the current was below 10 μA cm−2. Both optical and electrochemical behaviour indicate a strong synergistic effect arising within the bimetallic mosaic formed over the TiND.

In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a &beta, phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2&middot, g&minus, 1, a pore volume of 0.0042 cm3&middot, 1, and high electrochemical stability with an overpotential deviation around 330&ndash, 340 mV at 10 mA&middot, cm&minus, 2geo for 70 h.

Titanium dioxide nanotubes are regarded as one of the most important functional materials and due to their unique electronic properties, chemical stability and photocorrosion resistance, they find applications in, for example, highly efficient photocatalysis or perovskite solar cells. Nevertheless, modification of TiO2 nanotubes is required to overcome their main drawback, i.e. large energy bandgap (>3.2 eV) limiting their ability to capture solar light. In this work, we report the changes in optical and photoelectrochemical properties of well-separated TiO2 nanotubes that are tuned by varying the geometry of the material. The ordered tubular titania is formed via anodization in the presence of fluoride ions in diethylene glycol at elevated temperature. Length, inner diameter, wall thickness, and separation distance are described in function of synthesis parameters such as applied voltage and duration. The morphology and optical properties are characterized by means of scanning electron microscopy and UV–Vis spectroscopy techniques, respectively, while cyclic voltammetry, linear voltammetry and chronoamperometry are used to determine electrochemical/photoelectrochemical activity in different light conditions. The obtained results suggest a link between specific surface area, the width of the band-gap, and photoactivity, each of which could be individually optimised via anodization conditions. Moreover, the behaviour of the Mott-Schottky plot before and after 3 min of irradiation is studied indicating the positive shift of the flat band position and an increase in donor density values for all the obtained materials. The Mott-Schottky analysis was correlated with the linear voltammetry scans suggesting the important role of surface trapped holes. Presented in here results significantly supplement the current state-of-art regarding separated TiO2 nanotubes that are considered as not fully investigated and unappreciated class of titania materials which due to the exposure of inner and outer wall can be used for further modifications.

Electrochemical anodization is regarded as a facile and easily scalable fabrication method of titania nanotubes (TiO2NTs). However, due to the extended duration of calcination and further modifications, much faster alternatives are highly required. As a response to growing interest in laser modification of nanotube arrays, a comprehensive investigation of pulsed-laser irradiation and its effect onto TiO2NT properties has been carried out. The impact of irradiation onto the surface being placed at different angles in respect to the laser beam was studied and evaluated. The usage of the motorized table enables formation of laser-treated traces over the selected area. SEM and TEM analysis provides insight into morphological changes and shows partial melting of nanotubes surface, which is accompanied by the decrease of internal TiO2 tube diameter just below the melted region. Although structural and optical analysis consisting of Raman, photoluminescence and UV–Vis data indicate that presented method does not result in complete material crystallization, it promotes creation of advantageous localized states within TiO2 bandgap that may play a crucial role in charge separation. Moreover, impressive improvements to the mechanical properties resulting from the laser-modification are presented.

Non-enzymatic electrochemical platforms sensitive towards glucose presence have attracted a worldwide attention during last decades. We report on influence of solar light onto response of gold-titanium heterostructures prepared via controllable approach. The material based on Au nanoparticles orderly distributed over the structured titanium foil was obtained by electrochemical anodization followed by chemical etching, magnetron sputtering of gold and finally thermal treatment in the continuous regime. It is proven that the applied synthesis route leads to the enhanced visible light absorption boosting material photoactivity. Fabricated electrode immersed in the glucose containing solution and exposed to the solar light exhibits superior increase of oxidation current comparing to pristine substrate before thermal annealing. Photosensor is characterized by broad linear response up to 40 mM of glucose, limit of detection of 0.2 and 0.1 mM and sensitivity of 3.08 and 0.92 μA/cm2 in NaOH and PBS, respectively. It is concluded that the electrode exhibits enhanced performance taking advantage from plasmon resonance effect and the presence of thin titania passive film. Moreover, obtained material is stable under prolonged illumination and was verified in the presence of blood serum sample. Overall, presented results suggest that the impact of solar light should be taken into account during works on sensing devices.

This work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole, and graphitic groups. Nevertheless, it was possible to obtain a stable aqueous dispersion of NGOs, a prerequisite for the EPD process. According to SEM images, the EPD coatings were compact with minor defects. On the contrary, GO coating possessed cracks and large pores that resulted from gas evolution during electrolysis. Electrochemical studies showed that all coatings prevented copper from corrosion in saline solution, however, the nitrogenated coatings did not exhibit better anti-corrosion properties than reduced graphene oxide coating. A reasonable explanation of this finding is that some positive properties of the nitrogenated coatings, in terms of anti-corrosion action, like low hydrophilicity and good adhesion, were counteracted by their catalytic activity towards oxygen reduction reaction.

This work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 °C and 600 °C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after 600 °C, the electrochemical performance decreases considerably.

In this study, Fe–Pb–Si oxide glasses containing between 12.5 and 17.5 mol% Fe2O3 were prepared using two different methods comprising traditional melt-quenching and twin roller fast-cooling techniques. The topography and structure of the materials obtained were characterized by X-ray powder diffraction and scanning electron microscopy. All of the materials were found to be amorphous. The topography of most of the glasses comprised random or evenly distributed nanostructures, where the size and amount were dependent on the iron content and preparation technique. The thermal properties of the glasses were analyzed by differential scanning calorimetry, which showed that the glass transition temperatures varied between 529 °C and 552 °C. The electric conductivity and magnetic susceptibility of the glasses were analyzed by impedance spectroscopy and with an alternating current magnetic properties measurement system, respectively. The measurements of the electrical properties indicated a relatively low activation energy for direct current conductivity (∼0.5–0.68 eV), which is typical of the polaron hopping mechanism. All of the materials exhibited magnetic hysteresis loops and they were ferromagnetic.

A multi-tool analytical practice was used for the characterisation of a 16th century carpet manufactured in Cairo. A mild extraction method with hydrofluoric acid has been evaluated in order to isolate intact flavonoids and their glycosides, anthraquinones, tannins, and indigoids from fibre samples. High-performance liquid chromatography coupled to spectroscopic and mass spectrometric detectors was used for the identification of possible marker compounds with special attention paid to natural dyes present in the historical samples. Weld, young fustic, and soluble redwood dye were identified as the dye sources in yellow thread samples. Based on the developed method, it was possible to establish that red fibres were coloured with lac dye, whereas green fibre shades were obtained with indigo and weld. Tannin-containing plant material in combination with indigo and weld were used to obtain the brown hue of the thread. Hyphenation of high-performance liquid chromatography (HPLC) with quadrupole time-of-flight mass spectrometry (QTOF MS) and triple-quadrupole mass spectrometry (QqQ MS) enabled us to recognise four uncommon and thus-far unknown dye components that were also found in the historical samples. These compounds probably represent a unique fingerprint of dyed threads manufactured in a Turkish workshop. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) were used for the identification and characterisation of substrates and mordants present in the historical carpet. Carbon and oxygen were detected in large quantities as a part of the wool protein. The presence of aluminium, iron, and calcium indicated their usage as mordants. Trace amounts of copper, silica, and magnesium might originate from the contaminants. FT-IR analysis showed bands characteristic for woollen fibres and SEM micrographs defined the structure of the wool.

The number, morphology and elemental composition of nanoparticles (

Doping of TiO2 nanotube arrays with boron was realized via electrochemical treatment of as-anodized titania immersed in electrolyte containing boric acid. The photoactivity of doped and pure titania was examined by means of photoelectrochemical and photocatalytic response under UV–vis irradiation. The results showed that photocurrent density of B-TNTs is remarkably higher (7.5 times) than density of pure TiO2 nanotube arrays. Furthermore, the usage of doped samples as a catalytic material leads to a significant improvement in decomposition efficiency of methylene blue and in the efficient formation of hydroxyl radicals than is the case in the presence of titania. Keywords: Anodization, Nanotube, Boron-doped, Photoactivity, Titanium dioxide

The structure, optical and electrical properties of manganese borosilicate glasses of the composition xMnO–(80 − x)SiO2–20B2O3 (x = 40, 50, and 60 mol%) were investigated. The dependence of the glass structure on its composition was discussed and related to electrical properties. A separation of two amorphous phases was observed. It was suggested that one phase is MnO-rich and the other is SiO2-rich. It was found that the conductivity of MnO-rich phase is much higher than the conductivity of the other phase. The analysis of the valence states of manganese suggest that the transition metal ions are mainly present at second oxidation state. Magnetic susceptibility measurements show antiferromagnetic interactions in samples.

In this work the effects of electropolymerization conditions on the morphological properties and conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) film have been studied. PEDOT films were electrochemically synthesized in a one step process from acetonitrile solution containing 3,4-ethylenedioxythiophene (EDOT) and lithium perchlorate. Based on atomic force microscopy, scanning electron microscopy, cyclic voltammetry and impedance spectroscopy measurements, the morphological properties such as the of structure, double layer capacitance and thus the polymer surface area have been determined. It was shown that depending on the deposition conditions applied, different structures and film surface area could be obtained. Impedance measurements performed during deposition showed different resistance behavior and conductivity. The relationship between structure and conductivity of PEDOT film obtained under different deposition conditions has been discussed.

Cylindrospermopsin (CYN) is known to induce cytotoxic effects in eukaryotic cells although the exact mechanism underlying these alterations is not fully explained. Given that CYN was previously found to decrease the proliferation of human lymphocytes through DNA damage and cell cycle arrest followed by an increase in the apoptotic rate, the present study evaluated the possible involvement of reactive oxygen species (ROS) and oxidative stress in these cytopathic responses. The status of enzymatic antioxidants: superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) as well as level of lipid peroxidation (LO) under CYN influence in human lymphocytes were also studied. It was found that CYN exposure (0.01–1.0 μg/ml) induces a concentration-dependent increase in H 2 O 2 content within a time as short as 0.5 h, reaching its maximum level after 3 and 6 h. The highest H 2 O 2 content was accompanied by a significant decrease of SOD and CAT activity and an elevated level of GPx. Moreover, CYN treatment resulted in a detectable increase in LO. We conclude that ROS and the products of LO play an essential role in CYN-induced toxicity in human lymphocytes. Our study helps to elucidate the sequence of events caused by CYN in eukaryotic cells and explain the background for previously observed cytopathic responses.

A1. Carbonation A1. Precipitation A1. Solvents B1. Calcium compounds abstract Precipitated calcium carbonate particles were obtained during carbonation of calcium hydroxide slurry with carbon dioxide. Aqueous solutions of isopropyl alcohol, n-butanol and glycerol were used as solvents. Concentration of organic additives in the reactive mixture was from 0% to 20% (vol). Precipitation process were performed in a stirred tank reactor equipped with gas distributor. Multimodal courses of particles size distribution were determined for produced CaCO3 particles. Calcium carbonate as calcite was precipitated in all experiments. The mean Sauter diameter of CaCO3 particles decreased when the concentration of all used organic additives increased. The amount of small particle fraction in the product increased with the increasing concentration of organic solvents. Similar physical properties of used liquid phase resulted in the similar characteristics of obtained particles.

In this paper, thin perovskite layers between cathode material of solid oxide fuel cells and gadolinia-doped ceria buffer layer are investigated. Thin layers made of LaNi0.6Fe0.4O3-δ (LNF), La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), or SrTi0.65Fe0.35O3-δ (STF) were symmetrically deposited by spin coating method from metallo-organic polymer precursors on a Ce0.8Gd0.2O2-δ (CGO) substrate. Porous and about 40-μm-thick LNF cathodes were deposited on both sides of the substrate and sintered at 1100 °C. Different thicknesses of the thin perovskite layer were investigated in order to find the most effective one and to better understand its influence on the cathode/electrolyte interface. It was found that approximately 150 nm LNF or LSCF layer is sufficient to minimize interface resistance and improve cathode reproducibility. It was concluded that the thin perovskite layer increases contact area and improves the oxygen ion transport between the cathode and electrolyte without influencing the ox- ygen reduction reaction mechanism.

In this paper solid oxide fuel cells operating with dry synthetic biogas have been examined. In order to increase their stability the layers of CuO-CeO 2 , Cu 1.3 Mn 1.7 O 4 and Y 0.08 Sr 0.92 Ti 0.8 Fe 0.2 O 3 -δ have been deposited on the Ni-YSZ anode site. These layers should catalyze the internal biogas reforming and prevent the carbon deposition on the anode site. It has been found that CuO-CeO 2 and Cu 1.3 Mn 1.7 O 4 catalysts led to an increase of the stability (at least 7 days) of the fabricated fuel cells powered by biogas, whereas the unmodified fuel cell, as well as the fuel cell with Y 0.08 Sr 0.92 Ti 0.8 Fe 0.2 O 3 -δ catalyst degraded gradually with time. A significant amount of carbon nanofibers has been formed on the catalyst surface after fuel cell test. However, they have not formed in the anode area. The use of CuO-CeO 2 and Cu 1.3 Mn 1.7 O 4 catalysts prevented the carbon deposition on the anode site, and thus the fuel cell degradation was slower when operating with biogas fuel.

The nonlinear and linear electrical properties, topography, and microstructure of bismuth-vanadate ceramics, were studied. The structure was observed with the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal microscopy methods. The obtained results showed that ceramic is porous. Two phase transitions were determined with the use of DSC measurements. The linear and nonlinear ac complex conductivity was studied as the function of frequency, temperature, and ac voltage. The activation energy of dc conduction processes was evaluated. The temperature dependence of conductance and permittivity showed a specific behaviour in two temperatures which were in agreement with phase transition temperatures. The nonlinear impedance studies showed that the ratio of third harmonic to base frequency conductivity reached more than 0.20. Obtained nonlinearities achieved two maxima near phase transition temperatures.

In this work corrosion kinetics of the porous IN625 alloy is studied in the temperature range of 700 °C–800 °C in air and humidified hydrogen for up to 1000 h. Moreover, an effective and simple method of reducing corrosion rates of porous alloys by the infiltration of the rare earth elements is shown. Modification by the yttrium containing precursor reduces the corrosion rate by a factor of 50 in air at 700 °C so that the lifetime of the infiltrated alloy is greatly extended.

This report concerns carbonaceous electrodes doped with tin(II) oxide nanoparticles. Tin nanoparticles are obtained by pulsed laser ablation in water. Crystalline nanoparticles have been encapsulated in a carbonaceous matrix formed after pyrolysis of a mixture consisting of tin/tin(IV) oxide nanoparticles and gelatine. The obtained material is characterized by means of X-ray diffraction, selected area diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis. Battery charging/discharging tests exhibit a capacity of 580 mA h g−1 for current densities of 100 mA g−1. The cycling performance of the material suggests that the tested nanocomposite can be used as an anode for lithium-ion batteries.

Measurements of a system consisting of cathode/doped ceria diffusion barrier/doped zirconia electrolyte were made using two- and three-electrode configuration. Results obtained on a three-electrode measurement configuration were compared with and reflect the results obtained in two-electrode configuration. Three-electrode measurements allowed separating the impact of the symmetrical interface in the investigated system. They also enabled to obtain additional information about the investigated interface, such as the behavior of the system under an external polarization voltage. It has been shown that the 200 to 1200 nm thick CGO diffusion barrier layer fabricated by spray pyrolysis significantly reduces the polarization resistance of the interface. It also minimizes the impact of the polarization resistance in the presence of external polarization voltage.

The paper discusses the synthesis and performance of iodine doped titania nanotube arrays exhibited under irradiation. The doping procedure was performed as an additional, electrochemical process carried out after formation of nanotube arrays via anodization of the Ti substrate. The optical and structural properties were characterized using Raman, UV-vis, photoluminescence and X-ray photoelectron spectroscopy. The surface morphology and cross-section studies performed by means of scanning electron microscopy show that the ordered tubular architecture is not influenced by the doping method. However, iodine doping causes a reduction of bandgap energy and photoluminescence intensity. The nanotubular TiO2 electrodes have been monitored by electrochemical (using cyclic voltammetry and electrochemical impedance spectroscopy) and in situ UV-vis spectroelectrochemical measurements in contact with an aqueous electrolyte. Collected results show significant differences in electrochemical activity between pure and doped titania exhibited as i.e. change of Mott–Schottky relation or shift in the onset potential when a decrease in reflectance is initiated. The photocurrent density reached 155.2 and 142.2 μA cm−2 for iodine doped materials when KI and HIO4 were used as iodine precursors whereas only 25.6 μA cm−2 was registered for pure titania nanotubes under UV-vis illumination. Moreover, doped samples are far more efficient for the photodegradation progress than undoped material leading to decomposition of over 70% of methylene blue used as a model organic pollutant. The reported studies demonstrate for the first time the detailed optical, electrochemical and photoelectrochemical studies of iodine doped nanotube arrays.

Impedance spectroscopy is one of the most commonly performed measurements to characterize electronic and electrochemical systems. Impedance spectra have limited resolution and many different processes may overlap what could be the reason of obstructions in its proper later analysis. Up to date, there are three approaches to solve this problem: examining impedance spectra itself, fitting spectra with equivalent circuits, and calculating the distribution of relaxation times (DRT). The latter method does not require any model or further knowledge about the system. As a result of DRT calculation, a plot containing relatively narrow peaks related to relaxation process of measured system is obtained. Namely, the position of the peak is related to time constant of the process, while the area under the peak to relaxation resistance. The aim of this work is to test available fitting functions to calculate area under a peak for previously prepared model containing different equivalent circuit elements. Obtained results are validated using exact formulas describing distribution of relaxation times for mentioned elements.

The use of phage display to identify peptides with an ability to bind and synthesize Eu

In this study, we have demonstrated the fabrication of novel materials called boron-doped carbon nanowalls (B:CNWs), which are characterized by remarkable electrochemical properties such as high standard rate constant (k°), low peak-to-peak separation value (ΔE) for the oxidation and reduction processes of the [Fe(CN)6]3–/4– redox system, and low surface resistivity. The B:CNW samples were deposited by the microwave plasma-assisted chemical vapor deposition (CVD) using a gas mixture of H2/CH4/B2H6 and N2. Growth results in sharp-edged, flat, and long CNWs rich in sp2 as well as sp3 hybridized phases. The achieved high values of k° (1.1 × 10–2 cm s–1) and ΔE (85 mV) are much lower compared to those of the glassy carbon or undoped CNWs. The enhanced electrochemical performance of the B:CNW electrode facilitates the simultaneous detection of DNA purine bases: adenine and guanine. Both separated oxidation peaks for the independent determination of guanine and adenine were observed by means of cyclic voltammet...

Recently, an intensive research is carried out on plasmonic structures due to their potential application in many areas such as sensing, light harvesting and energy conversion and storage. In particular, a growing interest is observed in the Nanoparticle Over Mirror (NOM) structures for which the lithography and surface chemical functionalization represent the most popular production routes1. However, the application of those techniques is limited by the low efficacy, process complexity and chemical contamination of nanoparticles (NP). In this work, we report the contamination-free and low cost fabrication method of NOMs based on wet coating and ultrasonic-assisted nanocolloid drying process. The glass plates covered with magnetron sputtered 100 nm thick Au film and subsequently with Al2O3 layers (6 – 36 nm) by means of pulsed laser deposition are used as substrates. Au NPs are produced in the form of colloidal suspension by means of laser ablation in water using the 1064 nm, 6 ns Nd:YAG laser. The NOM synthesis is finalized by imposing of the Au NP suspension onto the as prepared Au-Al2O3/glass substrates and dried. To avoid NP agglomeration, the wet coated substrates are sonicated using 20W, 20 kHz ultrasound generator. SEM inspection of the obtained NOM structures confirms the positive sonication effect, i.e. the presence of agglomerate-free, homogenous layers. These consist of NPs (36 nm average diameter) which are characterized by the resonance absorption band at 528 nm. For NOM structures the UV-vis spectra reveal increased infrared activity and peak shift in agreement with theoretical modeling2. The NOM structure characterization is completed by analysis of the SEM and profilometry measurement results.

The ac and dc electrical conductivity of barium titanate doped bismuth-vanadate as-quenched and heat-treated materials was measured in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K with the impedance spectroscopy method. The microstructure was investigated by means of XRD, scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal microscopy. The obtained results showed that the structure of both as-quenched and heat-treated samples is not homogenous. Heat-treatment had significant influence on the amount, size and chemical composition of formed micro- and nanocrystallites. It also had great impact on the conduction process in investigated materials. As-quenched samples showed one relaxation process that was due to the overlapping polaron hopping. Conduction process in heat-treated samples may be caused by two different conduction mechanisms within nanostructures and in the matrix or by the interface polarization. Direct current conductivity increased and activation energies of this process decreased after heat-treatment. The experimental results were discussed based on a “core–shell” model and conductivity models collected by Elliot.

The ac and dc conductivity in iron–lead-borate glass samples was investigated in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by the means of atomic force microscopy (AFM) and the crystalline phases (if present) were identified by the means of X-ray diffractometry. Two types of ac electrical behaviour were observed. The first group of glass samples which contain up to 31% mol Fe 2 O 3 shows singular flattened semicircle in the impedance spectra. The second group of glass with over 25% mol Fe 2 O 3 shows two distinguishable semicircles indicating two relaxation processes. The results of structure investigation show that glass samples containing more than 2.5% mol Fe2O3 contain ball-shaped nanostructures. They have average size of an order of magnitude 100 nm. In XRD patterns for glass containing less than 19% mol Fe2O3 there are no diffraction peaks while in the patterns for samples with a larger amount of iron oxide some small peaks are present which indicate that some crystalline phases exist in these samples. In glass containing up to 19% iron oxide one process is responsible for conduction mechanism, small-polaron hopping. In the glass samples containing more of iron oxide, two dielectric relaxation processes were found. The second process may be caused by interface effect or conductivity process in the granules.

The linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show that the impedance spectra of all samples exhibit one large relaxation process and some additional small relaxation is present in glass containing 20 mol% and 25 mol% Fe2O3. The AFM micrographs show that in a subset of samples some nanostructures exist. Their size, shape, and quantity depend on the amount of Fe2O3 in the composition of the glass. The samples containing an amount of 15 mol% of Fe2O3 include the biggest nanostructures which are ball-shaped. EFM and MFM micrographs show that nanostructures exhibit different electrical and magnetic behaviors than the rest of the glass matrix. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity exponent s was determined and compared to theoretical models proposed by Elliott. It was found that while in the glass containing less than 15 mol% iron oxide, there is only one process responsible for conduction mechanism, the overlap polaron tunneling. In the other samples, a different conduction mechanism may coexist: quantum mechanical tunneling between semiconducting granules.

In order to find a relationship between structural and electrical properties, niobium and yttrium doped SrTiO3 ceramics were prepared via solid-state reaction. The samples were sintered in hydrogen and air conditions. The samples were also fabricated with a pore-former to obtain highly porous specimens. The electrical properties of Nb-doped SrTiO3 samples and yttrium and niobium co-doped SrTiO3 were compared. The comparable electrical properties were observed and discussed according to previous literature reports. It was noticed that the synthesis in a reducing hydrogen atmosphere can increase the solubility of dopants. Moreover, the samples sintered in air presented lower conductivity level and worse structural properties than the samples sintered in hydrogen. The explanation of obtained results was also suggested and discussed.

Nanolayers and bulk xerogels of Rhodamine 6G (Rh6G) in titanium dioxide (Rh6G/TiO2) were prepared using the sol–gel method. The spectroscopic and structural properties of these two types of hybrid matrices were studied as a function of dye concentration. In both cases absorption, fluorescence and time resolved emission spectra show the formation of fluorescent aggregates. The observed stronger changes in characteristics of bulk xerogels can be explained not only by the formation of aggregates but also by different structure of both materials.