Meta-analysis of CO2 conversion, energy efficiency, and other performance data of plasma-catalysis reactors with the open access PIONEER database

This paper brings the comparison of performances of CO2 conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field, organised in an open access online database. This tool is open to all users to carry out their own analyses, but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made, and ultimately to improve the efficiency of CO2 conversion by plasma-catalysis. The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO2 conversion processes, be it methanation, dry reforming of methane, methanolisation, or others. As a result of this rapid increase, there is a need for a set of standard procedures to rigorously compare performances of different systems. However, this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures. Fortunately however, the accumulated data within the CO2 plasma-catalysis community has become large enough to warrant so-called “big data” studies more familiar in the fields of medicine and the social sciences. To enable comparisons between multiple data sets and make future research more effective, this work proposes the first database on CO2 conversion performances by plasma-catalysis open to the whole community. This database has been initiated in the framework of a H2020 European project and is called the “PIONEER DataBase”. The database gathers a large amount of CO2 conversion performance data such as conversion rate, energy efficiency, and selectivity for numerous plasma sources coupled with or without a catalyst. Each data set is associated with metadata describing the gas mixture, the plasma source, the nature of the catalyst, and the form of coupling with the plasma. Beyond the database itself, a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public. The simple and fast visualisation of the state of the art puts new results into context, identifies literal gaps in data, and consequently points towards promising research routes. More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling. Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO2 plasma-catalytic studies. Finally, the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool

Sélectivité contrôlée avec différentes sources de plasma pour l'hydrogénation du CO2

L'un des plus grands défis de l'humanité en ce siècle est la lutte contre l'augmentation constante des gaz à effet de serre dans l'atmosphère, en particulier du dioxyde de carbone CO2. Diminuer ou stabiliser ces émissions en développant des solutions innovantes afin de capter et transformer (CCU) le CO2 inévitablement produit par les gaz sont challenges majeurs pour les prochaines décennies. Dans cette étude, nous nous concentrerons sur la réaction de méthanation du CO2 (réaction de Sabatier) comme une approche prometteuse pour la réduction du CO2 puisque le méthane généré peut être facilement stocké dans le réseau de gaz existant ou utilisé comme matière première pour la production de produits chimiques précieux. En évitant les conditions critiques, comme les hautes températures et pressions nécessaires dans l'approche thermique conventionnelle et en augmentant les exigences d'une production flexible par énergie renouvelable, il est possible de combiner la technologie plasma avec la catalyse. Malgré le fait que les principes généraux de la catalyse par plasma soient décrits dans la bibliographie, il s'agit encore d'un nouveau domaine de recherche avec de nombreux aspects non résolus à découvrir. Ainsi, dans ce travail, nous tenterons de montrer certains de ces aspects en étudiant l'impact des effets de promotion sur les propriétés du plasma dans un réacteur plasma à décharge à barrière diélectrique "DBD" à lit fixe, permettant de mettre en évidence la synergie entre le plasma et le catalyseur. Cette thèse, en tant qu'étude multidisciplinaire, se concentrera dans un premier temps sur l'effet des promoteurs et leur chargement optimal sur le catalyseur Ni/CeO2 pour la réaction de méthanation du CO2 en présence du plasma. Dans un deuxième temps, cette série de catalyseurs sera intentionnellement supportée sur des zéolites HUSY afin d'étudier l'effet des propriétés physico-chimiques du catalyseur à base de zéolite sur l'efficacité énergétique de la méthanation du CO2. Ce travail permettra d'établir une nouvelle méthodologie pour sélectionner les catalyseurs à base de zéolite les plus appropriés en termes d'efficacité énergétique pour la méthanisation du CO2 par plasma DBD. De cette façon, nous espérons ouvrir de nouvelles perspectives pour améliorer la synergie entre le plasma et le matériau de garnissage, afin de contribuer à la transition vers un avenir durable.One of the greatest challenges for humanity in this century is the fight against the constant increase of greenhouse gases in the atmosphere, in particular carbon dioxide CO2. Declining or stabilizing these emissions by developing innovative solutions in order to capture and transform (CCU) the inevitably gas produced CO2 are major challenges for the next decades. Here in this study, we will focus on the CO2 methanation reaction (Sabatier reaction) as a promising approach for CO2 reduction since the generated methane can be readily stored in the existing gas network or used as raw materials for valuable chemical production. By avoiding the critical conditions of high temperatures and pressure needed in conventional thermal approach and intersecting the requirements for flexible production by renewable energy can be achieved by combining plasma technology with catalysis. Despite the fact that the general principles of plasma catalysis are described, it is yet a new field of research with many unsolved aspects to be discovered. Hence, in this work, we will attempt to show some of these aspects by studying the impact of promotional effects on plasma properties in a packed bed Dielectric Barrier Discharge “DBD” plasma reactor, which allow to highlight the synergy between plasma and the catalyst. This PhD thesis as a multidisciplinary study, first will focus on the effect of promoters and their optimum loading on Ni/CeO2 catalyst for the CO2 methanation reaction in the presence of the plasma. In the second step this series of catalysts will be intentionally supported on HUSY zeolites to investigate the effect of physicochemical properties of the zeolite-based catalyst on the energy efficiency of CO2 methanation. This work will grant a new methodology to select the most appropriate zeolite-based catalysts in terms of energy efficiency for DBD plasma catalytic CO2 methanation. Under this way, we hope to open new insights to further improve the synergy between the plasma and the packing material, in order to help with the transition towards a sustainable future

Comparison of Chemical and Interpretative Methods: The Carbon-boron π-Bond as a Test Case

Quantum chemical calculations using DFT and NBO, ETS-NOCV, QTAIM and ELF interpretative approaches have been carried out on X-BH2+ borenium complexes for 39 divalent C-donor ligands X including various N-heterocyclic carbenes and carbones. The C-B bond length and the barrier of rotation around the C-B bond were calculated and compared with various descriptors of the C-B pi-bond strength obtained from the orbital localization, energy partitioning or topological methods. Two families of descriptors emerged: intrinsic indicators, which measure the intensity of the pi-bond in the investigated molecule, and relative indicators, among them the rotational barrier, which compare the studied molecule with its conformer in which the pi-interaction is prevented. Relative indicators are influenced by other interactions in addition to purely pi-interactions. For both families of descriptors, excellent correlations are obtained, showing that the interpretative methods, despite their conceptual differences, describe the same chemical properties. These results also reveal noticeable shortcomings in these methods, and some precautions that need to be taken to interpret their results adequately.<br /

On the Effect of Cobalt Promotion over Ni/CeO₂ Catalyst for CO₂ Thermal and Plasma Assisted Methanation

In recent years, carbon dioxide hydrogenation leading to synthetic fuels and value-added molecules has been proposed as a promising technology for stabilizing anthropogenic greenhouse gas emissions. Methanation or Sabatier are possible reactions to valorize the CO2. In the present work, thermal CO2 methanation and non-thermal plasma (NTP)-assisted CO2 methanation was performed over 15Ni/CeO2 promoted with 1 and 5 wt% of cobalt. The promotion effect of cobalt is proven both for plasma and thermal reaction and can mostly be linked with the basic properties of the materials

Comparison of Chemical and Interpretative Methods: the Carbon- Boron π-Bond as a Test Case

International audienceQuantum chemical calculations and NBO, ETS-NOCV, QTAIM and ELF interpretative approaches have been carried out on C-donor ligand-stabilized dihydrido borenium cations. Numerous descriptors of the C-B π-bond strength obtained from orbital localization, energy partitioning or topological methods as well as from structural and chemical parameters have been calculated for 39 C-donor ligands including N-heterocyclic carbenes and carbones. Comparison of the results allows the identification of relative and absolute descriptors of the π interaction. For both families of descriptors excellent correlations are obtained. This enables the establishment of a π-donation capability scale and shows that the interpretative methods, despite their conceptual differences, describe the same chemical properties. These results also reveal noticeable shortcomings in these popular methods, and some precautions that need to be taken to interpret their results adequately