In this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4- (PEDOT/ClO4-) films were fabricated using an electrodeposition method method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate that NO2 causes overoxidation of the PEDOT polymer (PEDOT/ClO4- film) which leads to resistance increase and irreversible response. In contrast, the PEDOT-RGO response in the presence of NO2 is reversible. During short NO2 exposure, PEDOT from the PEDOT-RGO composite does not react to the gas but the presence of RGO in the PEDOT-RGO composite does not affect the overoxidation potential. It was found that the nitrogen dioxide reacts more readily to reduced graphene oxide, thus RGO "protects" the polymer against the adverse overoxidation process. (C) 2018 Elsevier B.V. All rights reserved.

This work discusses sensing performance dependence of PEDOT polymer and its composites on the counter ions used in the polymerization process. The sensors based on PEDOT-RGO composite show reversible response to NO2, while on PEDOT/LiClO4 irreversible. As a result, PEDOT-RGO could be used as a typical gas sensor, while sensor based PEDOT/LiClO4 could be used as an integrating gas sensor, also known as an accumulating gas sensor. The irreversible nature of the response occurs also in the case of polypyrrole/LiClO4. The nature of PPy response to toxic gases does not allow using the sensor in conventional way. However, the information about the concentration could be acquired from the response using a linear approximation, a non-linear approximation and a tangent method.

This work presents a simple and fully electrochemical route for the polymerization of poly(3,4-ethylenedioxytiophene) (PEDOT) films for fabricating a NO2 gas sensor prepared by electropolymerization of 3,4-Ethylenedioxythiophene (EDOT) monomer in lithium perchlorate/acetonitrile solution. The main aim of this study is to determine the sensing properties of conductive polymer at elevated temperatures. The effects of the humidity, working temperature and sensing response of the PEDOT to environmental gases are investigated. The use of the PEDOT film as NO2 gas meter of total flow of NO2 is evaluated. (C) 2017 Elsevier B.V. All rights reserved.

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 1000h. 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.

The nature of polypyrrole response to toxic gases does not allow using the sensor in a conventional way. The main aim of this study is to acquire the information about the concentration using different approaches: a linear approximation, a non-linear approximation and a tangent method. In this paper a two-steps procedure for sensor response measurements has been utilized. Polypyrrole films were electrochemically synthesized on the interdigitated electrodes. Gas sensing measurements of polypyrrole based sensor were carried out at room temperature. The influence of the flow rate on the sensing performance to NH3 were investigated. The preliminary studies of aging of the sensor were also explored.

A graphene oxide (GO), reduced graphene oxide (RGO) and poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO composite) gas sensors were successfully fabricated using an electrodeposition method. The electrodeposition was carried out in aqueous GO dispersions. To obtain RGO and PEDOT-RGO, the electrochemical reduction of GO and PEDOT-GO was carried out in 0.1 M KCl at a constant potential of -0.85 V. The GO, RGO and PEDOT-RGO composite were characterized by scanning electron microscopy (SEM). The fabricated sensors showed sensitivity to NO2 gas. In this work the sensing response of GO, RGO and PEDOT-RGO in NO2 at elevated temperatures were investigated. The influence of the operating temperature on the gas sensing response were compared. The role of the polymer and RGO in PEDOT-RGO composite was discussed. The results are discussed in light of recent literature on graphene sensors.

In this work a commercially available porous Hastelloy X alloy is characterized in terms of high temperature corrosion resistance. The alloy was oxidized in the temperature range from 500 degrees C to 900 degrees C in air and humidified hydrogen for 100 hours. Corrosion rates and porosity changes were measured. Microstructural characterization was performed using X-ray diffractometry and scanning electron microscopy. Results show that porous alloys oxidize rapidly even for the relatively short time of the study. Long term operation in fuel cell conditions seems feasible especially in hydrogen atmosphere at temperatures preferably not exceeding 700 degrees C. (C) 2016 The Electrochemical Society. All rights reserved.

This work presents a simple and fully electrochemical route used for fabricating of a NO2 gas sensor made of reduced-graphene-oxide-poly(3,4-ethylenedioxythiophene) composite film. The sensing platform was fabricated from alumina substrate and equipped with gold interdigitated electrodes and built-in heater. The temperature distribution on the surface of interdigitated electrodes was investigated by a thermal imaging camera and compared with numerical simulations. The sensing film was prepared on sensing platform by electropolymerization of EDOT monomer and graphene oxide solution and reduction in 0.1M KCl. A scanning electron microscopy and Raman spectroscopy of the sensing film were performed. Gas sensing measurements were carried out at elevated temperatures. The effects of the operating and annealing temperature of the gas sensing film to NO2 on the sensing performance were investigated. The response characteristics in NO2 at elevated temperatures in a tube furnace and using a built-in heater were compared. The effect of the flow rate and relative humidity was also investigated.

The concentration or the partial pressure of oxygen in an environment can be determined using different measuring principles. For high temperature measurements of oxygen, ceramic-based sensors are the most practical. They are simple in construction, exploration and maintenance. A typical oxygen potentiometric sensor consists of an oxygen ion conducting solid electrolyte and two electrodes deposited on the two sides of the electrolyte.In this paper different structures of potentiometric oxygen sensors with a solid state reference electrode were fabricated and investigated. The fabricated structures consisted of oxygen ion conducting solid electrolyte from yttria stabilized zirconia, a sensing platinum electrode and nickel-nickel oxide reference electrode. The mixture of nickel-nickel oxide was selected as the reference electrode because it provides reliable electrochemical potential in contact with oxygen conducting electrolyte. To avoid oxidation of nickel the reference electrode is sealed from ambient and the mixture of nickel-nickel oxide was formed electrochemically from nickel oxide after sealing. The effectiveness of the sealing quality and the effectiveness of nickel nickel oxide mixture formation was investigated by impedance spectroscopy.

Solid oxide fuel cells (SOFCs) are one of the most promising energy conversion devices due to their high efficiency, low pollution and fuel flexibility. Unfortunately, when hydrocarbons are used as a fuel, for example in the form of a biogas, solid carbon can deposit on the anode surface. This process leads to the degradation of the fuel cell performance. A possible solution to this problem is to apply an additional catalytic material, which would improve catalytic activity towards the direct internal reforming of the biogas.In this work three catalytic materials were investigated towards the biogas reforming: Cu1.3Mn1.7O4, Y0.08Sr0.92Ti0.8Fe0.2O3 (-) (delta) and CeCu2O4. Materials were infiltrated into the Ni/YSZ cermet and YSZ structure. Their catalytic activities were tested in a synthetic biogas (mixture of 60% of methane and 40% of carbon dioxide) using FTIR spectroscopy of the outlet gases. Infiltration with catalytic materials improved the catalytic properties of supports, however, did not reduce the carbon formation rate. (C) 2013 Elsevier B.V. All rights reserved.

W pracy przebadane zostaly mozliwości zastosowania metody pirolizy aerozolowej do wytwarzania warstw z tlenku cyrkonu stabilizowanego itrem na podlozu ze stali nierdzewnej 316L.

To further understand the suitability of Ni-Cr-base alloy for solid oxide fuel cell (SOFC), a commercial Ni-Cr-Fe-Mo alloy, Hastelloy X was selected and evaluated for oxidation behaviour under high temperature conditions. HastelloyX was chosen due to its unusual resistance to oxidizing, reducing and neutral atmospheres. For long term stability of metal supported fuel cell, the corrosion resistance plays a vital role and must be enhanced. Cyclic thermogravimetric analysis, X-ray diffractometry and SEM imaging were used to describe properties of these porous alloy. The influence of porosity on resulting properties was also elucidated. The high temperature corrosion rate is high and is strongly influenced by the porosity level. Open porosity decreases rapidly upon oxidation at 800 oC.

W pracy sprawdzony zostal wplyw warstw ochronnych na poprawe odporności korozyjnej stali 316L. Jako warstwy ochronne zastosowano material tlenku cyrkonu stabilizowanego itrem.