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Electrochemical NOx sensors based on yttria-stabilized zirconia (YSZ) are commercialized to detect overall NOx concentrations in Diesel exhausts without distinction between NO and NO 2 . To overcome this inconvenient, a high-sensitive sensor based on selective electrochemical reduction of NO 2 is proposed. An electrochemical cell consisting of three metallic electrodes on solid-state electrolyte (YSZ) operating under electric polarization between a gold working electrode and a platinum counter electrode allows selective NO 2 detection at 400-550 °C with high sensitivity, and without any significant interferences to other gases like hydrocarbons, carbon monoxide and also ammonia and nitrogen monoxide. A mechanism based on cathodic overpotential is proposed. [ABSTRACT FROM AUTHOR]

This study reports on the influence of the polarization applied between platinum electrodes of a resistive soot sensor. The conductance measured between these electrodes represents the sensor response which increases during soot deposition over time at fixed parameters (soot flow, polarization). It is observed that a maximum response is obtained for an optimum polarization. This behavior is explained by equilibrium between the creation and destruction of inter-electrodes soot bridges. [ABSTRACT FROM AUTHOR]

A resistive soot sensor for diesel particulate filter (DPF) failure detection was developed in previous works. By measuring the conductance between two Pt electrodes, this sensor is able to detect a low leakage from the DPF but only provides soot mass information. In this study, we have characterized and determined the key parameters that influence the sensor response, i.e. the conductance with the aim to build a model that could provide soot number measurements. First results show a dependency of the sensor response with the soot mass concentration and the polarization level of the electrodes. [ABSTRACT FROM AUTHOR]

Abstract: The first Chinese and English representatives of the Mesozoic gomphid family Proterogomphidae are described, respectively Lingomphus magnificus gen. et sp. nov., and Cordulagomphus europaeus sp. nov. A phylogenetic analysis of the most ‘basal’ gomphid lineages is proposed, showing the monophyly of the Proterogomphidae and the position of Lingomphus as sister group of all other representatives of this family. C. europaeus is the first Eurasiatic representative of the subfamily Cordulagomphinae that was previously restricted to the Lower Cretaceous of Crato Formation (South America). The Proterogomphidae has a known distribution very similar to those of several other Lower Cretaceous insect groups, viz. Asia, Europe, and South America, showing that the distribution of the climates and land masses at that time was not a ‘serious’ impediment for the displacements of these organisms. [Copyright &y& Elsevier]

Abstract: The present work aims to develop a sensor that can leave the laboratory and be industrialised. For this reason potentiometric sensors based on a solid electrolyte YSZ and 2 metallic electrodes (platinum and gold) were fabricated by screenprinting technology and were tested in a laboratory test bench for different concentrations of CO, NO and NO2 in oxygen rich atmosphere. By deposing a catalytic filter consisting of 1.7%Pt dispersed in alumina directly on the electrodes, it was shown that the selectivity towards NOx could be highly reinforced. This filter was characterized by the use of SEM, TPD, and XRD technology. [Copyright &y& Elsevier]

Abstract: A new NO x storage-reduction electrochemical catalyst has been prepared from a polycrystalline Pt film deposited on 8mol% Y2O3-stabilized ZrO2 (YSZ) solid electrolyte. BaO has been added onto the Pt film by impregnation method. The NO x storage capacity of Pt-BaO/YSZ system was investigated at 350°C and 400°C under lean conditions. Results have shown that the electrochemical catalyst was effective for NO x storage. When nitric oxides are fully stored, the catalyst potential is high and reaches its maximum. On the other hand, when a part of NO and also NO2 desorb to the gas phase, the catalyst potential remarkably drops and finally stabilizes when no more NO x storage occurs but only the reaction of NO oxidation into NO2. Furthermore, the investigation has clearly demonstrated that the catalyst potential variation versus temperature or chemical composition is an effective indicator for in situ following the NO x storage-reduction process, i.e. the storage as well as the regeneration phase. The catalyst potential variations during NO x storage process was explained in terms of oxygen coverage modifications on the Pt. [Copyright &y& Elsevier]

The development of sustainable processes for the recycling of plastic is a major environmental issue to reduce the pollution by this kind of waste. The electro-oxidation of plastic wastes in electrolysers powered by renewable energies is a promising option to produce hydrogen at low temperature while diminishing the energy demand compared to Oxygen Evolution Reaction (OER). Poly (methyl-methacrylate) (PMMA) particles, a widely used polymer, were dissolved (0.1–2% wt.) in an isopropanol(IPA)/H 2 O binary solvent and electro-oxidized on Pt/C-based electrodes in a liquid batch electrochemical cell at 70 °C in acidic media. Despite the dissolution strategy, polymer macromolecules partially block the accessibility of the active sites of a commercial electrode and strongly degrades its electrochemical performances mainly linked to IPA electro-oxidation. The preparation of a more porous electrode supported on carbon paper was found to strongly hinder this deactivation. Furthermore, the electrooxidation of PMMA or PMMA-derived molecules can be performed during cyclic voltammetries up to 1.4 V and chrono-amperometries at 1.4 V. • First time: direct PMMA electrolysis as a promising technology for H 2 production. • Study of electrochemical oxidation of PMMA particles dissolved in binary solvents. • Fundamental understanding: Main advantages and limitations of this approach. [ABSTRACT FROM AUTHOR]

Abstract: A honeycomb monolith of YSZ (yttria stabilized zirconia) was used, for the first time, as a solid electrolyte to perform electrochemical promotion of the deep oxidation of methane. The goal of this study was to validate the concept of Electrochemical Promotion of Catalysis (EPOC) by using Pd particles dispersed on the channels surface of a YSZ dense honeycomb monolith. The Pd catalyst was an effective material as methane conversion reached 20% at about 320°C. The catalytic properties of the monolithic electrochemical catalyst were investigated upon electrical polarization at 400°C. Non faradaic effects were observed both under positive and negative polarizations with a maximum of the faradaic efficiency of 47. [Copyright &y& Elsevier]

Abstract: Due to the great importance of automotive exhaust gas treatment, the catalytic activity was investigated in selective catalytic reduction of NO by propene on Pt films – with controlled microstructure – deposited on YSZ (8 mol% Y2O3-doped ZrO2) by electrostatic spray deposition. This technique requires low Pt loadings in order to reduce costs and also to achieve high Pt particles dispersion with good reproducibility. This kind of electrochemical catalysts was found to be effective for NO reduction by propene in the presence of oxygen. A dense Pt film was found to be the most suitable. Furthermore, we have demonstrated that these electrochemical catalysts can implement the concept of electrochemical promotion of catalysis (EPOC). [Copyright &y& Elsevier]

The production of H 2 via electrolysis seems to be the best alternative to traditional catalytic reforming processes. The electrolysis of lignin allows to produce pure H 2 while valorizing a low-price biomass waste with (theoretically) lower energy requirements than water electrolysis. Previous studies were published in the last years dealing with the electro-oxidation of lignin on Ni-based catalysts. Ni is a robust non-expensive metal that presents a wide variety of oxidation states and phase transitions. To this date, it is still not completely clear how these states/transitions activate the lignin molecule. The aim of this study is to get more insights into the cleavage of the main chemical bonds present in the complex lignin structure over different Ni oxidation states. A Ni/C catalyst, prepared by the polyol method, was thoroughly characterized and tested for the electro-oxidation of both, lignin and 2-phenoxyethanol, where the latter is a model molecule representative of the quintessential β-O-4 linkage in lignin. • Lignin electrolysis as a promising technology for H 2 production. • Electrochemical study with model molecule: Fundamental understanding. • New insights into lignin electro-oxidation on different Ni phases/oxidation states. [ABSTRACT FROM AUTHOR]

• The soot oxidation catalytic activity is linked with the Ag surface concentration. • The ignition of the soot combustion process occurs on Ag nanoparticles. • Ag nanoparticles supported on YSZ only promote the run-away of the soot combustion. • Catalysts based on SiO 2 , ZrO 2 and YSZ exhibit a remarkable hydrothermal stability. This study investigates the catalytic activity for soot combustion of Ag nanoparticles dispersed on various supports showing different redox properties. Temperature programmed soot oxidation and isotopic exchange experiments were performed to assess the impact of the soot/catalyst contact, the oxygen partial pressure and the ageing toward activity. Three different contact modes have been used to clearly highlight the catalytic performances: loose, tight and supertight. Whatever the support, in both loose and tight contact modes, the catalytic performances are linked with the Ag surface concentration which was found to be high on zirconia-based catalysts and low on ceria-zirconia. The ignition of the soot combustion process occurs on Ag nanoparticles except for catalysts supported on Yttria-Stabilized Zirconia (YSZ), a pure oxygen ionic conductor, where Ag nanoparticles only promote the run-away of the reaction at higher temperatures. Catalysts based on SiO 2 , ZrO 2 and YSZ exhibit a remarkable hydrothermal stability as performances in tight contact mode are fairly similar after the hydrothermal ageing. [ABSTRACT FROM AUTHOR]

• Pd nanoparticles supported on Co 3 O 4 have been promoted via EPOC for CH 4 oxidation. • Positive potential enhances the catalytic rate of the supported catalyst by 250%. • The Co 3 O 4 support is a mixed electronic/ionic conductor at elevated temperatures. • Nanodispersed catalysts are partly promoted via the EPOC ion migration mechanism. During the last two decades the Electrochemical Promotion of Catalysis (EPOC) phenomenon has been studied extensively for many catalytic reactions including hydrocarbon oxidation reactions and hydrogenations. In the majority of the studies, the catalysts/electrodes consisted of porous noble metal films (Pt, Pd, Rh) prepared, for instance, by calcination of organometallic pastes. This results in low metal dispersion and low active surface area, limiting therefore the overall catalytic activity. In view of further practical application of the EPOC phenomenon to industrial catalysts, we should be able to enhance the activity of nanodispersed materials. In this study, for the very first time, we observed an enhanced catalytic activity of a Pd nanodispersed catalyst supported on a porous Co 3 O 4 semiconductor film. The Pd/Co 3 O 4 composite powder was deposited on an yttria-stabilized zirconia (YSZ) solid electrolyte without the presence of an interlayer film. The observed enhancement was non-Faradaic, with Faradaic efficiency values as high as 80. The Pd/Co 3 O 4 catalyst was characterized thoroughly by means of a wide variety of physicochemical techniques, such as TEM, SEM, TGA, ICP and BET. In addition, this material was further compared with a classical Pd/YSZ metallic film, prepared by calcination of an organometallic paste. This allows for a comparison of metal-support interactions (MSI) and the EPOC effect. Using supported catalysts as catalytic films for electrochemical promotion studies may lead to the practical utilization of EPOC in the chemical industry or in gas exhaust treatment. [ABSTRACT FROM AUTHOR]

This paper is a comprehensive study dealing with the parameters that influence the response of a resistive soot sensor which was developed for Diesel Particulate Filter (DPF) failure detection in a past project. From the conductance measurement between two Pt electrodes, and a regeneration strategy, this kind of sensor can provide the weight concentration of particulate matter (PM). In this study, we have characterized and determined the key parameters such as the PM distribution size and the polarization voltage between the electrodes that could influence the sensor response. First results show that the sensor response strongly depends on the polarization voltage applied between the two electrodes. [ABSTRACT FROM AUTHOR]

Herein, we investigate the interplay between a photocatalyst (TiO 2) and a catalyst (Pt/TiO 2 and Pt/CeO 2) for the oxidation of formaldehyde and toluene at room temperature. A luminous textile is used as support and as light source for the photocatalyst. Our results indicate that the presence of the catalyst and the photocatalyst increases the catalytic performance for the oxidation of formaldehyde, while the photocatalytic performance for toluene oxidation decreases. The overall performance (toluene and formaldehyde degradation) of the system can be optimized with respect to the choice of support for the catalyst (e.g. TiO 2 or CeO 2), the quantity of Pt used, and the ratio between the catalyst and photocatalyst. In addition, different configurations of the photocatalyst and the catalyst on the textile are studied: under leaching and flow-through gas streams, catalyst and photocatalyst deposition on the same and opposite site of the textile are tested. The performance of the system can be optimized by adapting a configuration where the gas stream goes through the textile, while the deposition side of the catalyst and/or photocatalyst with respect to the gas stream is of minor importance. Schematic illustration of the degradation mechanism of volatile organic compounds (VOC) by coupling photocatalysis and catalysis using a luminous textile with optical fibers. [Display omitted] • Room temperature oxidation of toluene and formaldehyde. • Coupling of photocatalyst and catalyst on an optical fiber textile enhances formaldehyde oxidation. • Pt/CeO 2 shows higher performance than Pt/TiO 2 for catalytic formaldehyde oxidation at room temperature. • Flow-through conditions are more effective than leaching gas streams. [ABSTRACT FROM AUTHOR]