Role of Plasma Catalysis in the Microwave Plasma‐Assisted Conversion of CO2

Climate change and global warming caused by the increasing emissions of greenhouse gases (such as CO2) recently attract attention of the scientific community. The combination of plasma and catalysis is of great interest for turning plasma chemistry in applications related to pollution and energy issues. In this chapter, our recent research efforts related to optimization of the conversion of CO2 and CO2/H2O mixtures in a pulsed surface‐wave sustained microwave discharge are presented. The effects of different plasma operating conditions and catalyst preparation methods on the CO2 conversion and its energy efficiency are discussed. It is demonstrated that, compared to the plasma‐only case, the CO2 conversion and energy efficiency can be enhanced by a factor of ∼2.1 by selecting the appropriate conditions. The catalyst characterization shows that Ar plasma treatment results in a higher density of oxygen vacancies and a comparatively uniform distribution of NiO on the TiO2 surface, which strongly influence CO2 conversion and energy efficiencies of this process. The dissociative electron attachment of CO2 at the catalyst surface enhanced by the oxygen vacancies and plasma electrons may explain the increase of conversion and energy efficiencies in this case. A mechanism of plasma‐catalytic conversion of CO2 at the catalyst surface in CO2 and CO2/H2O mixtures is proposed

Enhancing the Greenhouse Gas Conversion Efficiency in Microwave Discharges by Power Modulation

Scientific interest to the plasma-assisted greenhouse gas conversion continuously increases nowadays, as a part of the global Green Energy activities. Among the plasma sources suitable for conversion of CO2 and other greenhouse gases, the non-equilibrium (low-temperature) discharges where the electron temperature is considerably higher than the gas temperature, represent special interest. The flowing gas discharges sustained by microwave radiation are proven to be especially suitable for molecular gas conversion due to high degree of non-equilibrium they possess. In this Chapter the optimization of CO2 conversion efficiency in microwave discharges working in pulsed regime is considered. The pulsed energy delivery represents new approach for maximization of CO2 conversion solely based on the discharge “fine-tuning”, i. e. without the additional power expenses. In our work several discharge parameters along the gas flow direction in the discharge have been studied using various diagnostic techniques, such as optical actinometry, laser-induced fluorescence, and gas chromatography. The results show that CO2 conversion efficiency can be essentially increased solely based on the plasma pulse frequency tuning. The obtained results are explained by the relation between the plasma pulse parameters and the characteristic time of the relevant energy transfer processes in the discharge

Une cachette d’objets de valeur des années 60 apr. J.-C. dans une <i>villa</i> de la cité des Nerviens (Merbes-le-Château, Belgique)

International audienceDie gallo-römische villa von Champ de Saint-Éloi in Merbes-le-Château (Belgien) ist an der Sambre im äußersten Osten der civitas der Nervier gelegen. Im 2. und 3. Jh. unserer Zeit besaß sie einen imposanten Wohnbereich und mehrere Gebäude mit zugleich wirtschaftlicher und dekorativer Funktion. Im Hauptgebäude wurde in einem kleinen eingetieften Raum ein Depot mit Wertsachen entdeckt. Neben zwei Kesseln aus Kupferlegierung enthielt das Depot ein Kästchen, in dem sich zwei Silberlöffel, eine Börse mit 122 Antoninianen, ein Glasfläschchen und vier abgenutzte auf eine den Danubischen Reitern gewidmete Votivplatte gelegte Sesterzen befanden. Die Platte aus verzinnter Kupferlegierung ist in zweifacher Hinsicht außergewöhnlich, erstens weil diese Platten in den westlichen Provinzen sehr selten sind und zweitens aufgrund der hohen Qualität ihrer Ausführung und ihres Dekors. Die Originalität des Depots, das in den Jahren um 260 unserer Zeit vergraben wurde, beruht auf der Vielfältigkeit seiner Zusammensetzung aus Alltagsgegenständen, Wertobjekten und einem religiösen Gegenstand.The Gallo-Roman villa at Champ de Saint-Éloi in Merbes-le-Château (Belgium) lies by the river Sambre, at the eastern limit of the civitas Nerviorum. During the 2nd and 3rd centuries it was constituted of an imposing dwelling with adjacent buildings for economic functions and ornamental structures. A hoard of precious items was recovered inside the main building, in a small semi-buried room. It consists of two copper-allied caldrons and of a small casket containing two silver spoons, a purse with 122 silver antoniniani, a glass flask and four worn sestertii deposited on a plaque dedicated to the Danubian Riders. This copper-allied tinned plaque is remarkable for its rarity in the western provinces as for the high technical degree quality of its decoration. The originality of the hoard, buried in the 260s AD, comes from its heterogeneous contents: daily and precious items and a religious object are mixed.La villa gallo-romaine du Champ de Saint-Éloi à Merbes-le-Château (Belgique) est implantée en bordure de la Sambre, à l’extrémité orientale de la cité des Nerviens. Elle comportait, aux IIe et IIIe s. apr. J.-C., un imposant corps de logis et plusieurs bâtiments à fonctions économique et ornementale. Le site a également livré un dépôt d’objets précieux, découvert à l’intérieur du bâtiment principal dans une petite pièce semi-enterrée. Il se compose de deux chaudrons en alliage de cuivre et d’un petit coffret contenant deux cuillères en argent, une bourse de 122 antoniniens en argent, une fiole en verre, ainsi que quatre sesterces usés posés sur une plaquette dédiée aux Cavaliers danubiens. Celle-ci, en alliage de cuivre étamée, est exceptionnelle tant par sa rareté dans les provinces occidentales que par la qualité technique de son décor. L’originalité du dépôt, dont l’enfouissement est daté des années 260 apr. J.-C., tient dans sa composition hétérogène, mêlant des objets de la vie courante, des biens précieux et une pièce à caractère religieux

Recent developments in Vacuum arc surface treatments

conférence invitéeinfo:eu-repo/semantics/publishe

A review on the preparation of nanocomposite films by vacuum arc

conférence invitéeinfo:eu-repo/semantics/publishe

Ultra-hard DLC-based coatings

Conférence invitéeinfo:eu-repo/semantics/publishe

Contrôle et caractérisation fine de multicouches minces

info:eu-repo/semantics/publishe

Superlattices: preparation and characterization

conférence invitéeinfo:eu-repo/semantics/publishe

Cathodic arc evaporation and its applications to thin film synthesis

E-MRS short course ‘Materials Surface Processing (MATSUP): Deposition and Characterization of Surface Coatings and Thin Films.” (May 29-30, 2005, Strasbourg, France), cours invitéinfo:eu-repo/semantics/publishe