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Activity Funded

Plasma-Surface-Interaction (Data and Tools) COupled Modelling

Interação-Plasma-Superfície (Dados e ferramenTas) Modelização aCOplada

Reference
2022.04128.PTDC
Project Start Date
2023-03-12
Project End Date
2026-09-11
Principal Investigator
Coinvestigator
Scientific Area
Exact sciences
Funding Program
Concurso de Projetos de I&D em Todos os Domínios Científicos - 2022 - ICDT

Abstract

Project "Plasma-Surface-Interaction (Data and Tools) COupled Modelling" (PSI.COM) addresses the coupled modelling of the plasma-surface chemistry in N2-H2 mixtures, comprising several exciting endeavours: bridging the gap between volume and surface reactivity in plasma simulations; exploring the full potential of high-quality controlled measurements in an interplay with self-consistent time-dependent kinetic simulations; embracing screening/reduction of chemistry schemes as key-component of modelling; and publishing validated data in web-based platforms. Understanding the main kinetic paths leading to the synthesis of NH3 in N2-H2 plasmas has topical interest for the large-scale production of fertilizers at low cost and the mitigation of NH3 generation in fusion machines. And tackling this subject opens other research avenues: - identifying the main species and the most relevant volume/surface mechanisms controlling the non-equilibrium behaviour of N2-H2 plasmas; - quantifying the contribution of these mechanisms to the uncertainty in modelling results; - exploring the influence of pulsed excitations in the gas/plasma chemistry and energy exchanges; - optimizing the plasma-assisted production of ammonia; - proposing an ontology to (re)define a database for plasma-surface chemistry. These challenging issues will be addressed in PSI.COM, leveraging on complementary expertise in modelling and diagnostics of low-temperature plasmas (LTP) from group N-PRiME (N-Plasmas Reactive: Modelling and Engineering, IPFN) and our collaborators from LPP (Laboratoire de Physique des Plasmas, EP). The description of plasma-surface interactions (PSI), including feedback effects on the original plasma/surface state, is an essential component of predictive modelling for achieving fundamental understanding and enabling plasma-processing optimisation and control. The lack of reliable surface data is often invoked to avoid extending models to PSI. However, an intelligent interplay with dedicated experiments can provide information about the evolution of the plasma and the surface. The discrimination of species and mechanisms can be boosted by introducing a time-dependent analysis of repetitive-pulsed glow discharges and their afterglows (monitoring also gas/wall temperatures), for a ~1cm radius cylindrical configuration, at ~10 mA and ~1-10 Torr, with various catalysts. Indeed, AC/DC glow discharges have proved to be excellent testbeds for modelling, due to the quiescent plasmas they create, and revealed promising results in the plasma-assisted production of ammonia at high-yield, when using Ag-coated quartz as both electrode and catalyst. A N2-H2 chemistry scheme will be validated by confronting optical/laser/mass spectroscopic diagnostics and self-consistent simulations obtained with the LisbOn KInetics (LoKI) tool, advancing knowledge on the electron and the heavy-species kinetics in the plasma volume, the transport of species towards the wall and the surface kinetics. The current features of LoKI will be further extended to a full time-dependent description, coupling the Boltzmann/Chemistry solvers, integrating the description of surface species with catalyst-dependent parameters, and including the gas/plasma thermal balance. A web-version of the Boltzmann solver (LoKI-B) will also be developed, using an application-oriented GUI as interface foronline calculations. The validated N2-H2 chemistry scheme will be reduced to those mechanisms effectively contributing to the chemical output and pathways, by deploying a set of LoKI-tools for sensitivity analysis (SA) that restrict the workspace to that effectively analysed in the experiments, screen the mechanisms by identifying the most influential input data to the output results, and quantify uncertainties in the model predictions. The automated LoKI-tools for SA will include approaches used in the context of machine learning, to optimize the methods employed, reduce computational costs and obtain improved conclusions for model reduction. As outcome, we will identify the main kinetic paths for the synthesis of NH3 in N2-H2 plasmas, providing clues to optimize this plasma-assisted process. The final N2-H2 scheme and data will be published in open-access web-based platforms, namely the existing LXCat for electron scattering and the future CHEMCat for plasma chemistry mechanisms. We will take an active part (scientific and technical) in the community effort for the evolution/design of these databases, providing guidance on the definition of standards for naming species, classifying reactions and organizing relevant data; on the choice of complete and unambiguous formats for data exchange; and on the efficient storage and retrieval of these data. The accomplishment of these tasks, to be developed in close partnership with the stakeholders of LXCat, are key to the dissemination of plasma-chemistry schemes and data in view of the future definition of LTP "reaction mechanisms".

Institutions

Main Institutions

  • Associação do Instituto Superior Técnico para a Investigação e Desenvolvimento (IST-ID)

Other Institutions

  • École Polytechnique (EP)
  • Universidade do Minho (UMinho)

Funding 249.149,99 €

Fundação para a Ciência e a Tecnologia (FCT) - Portugal

249.149,99 €