Job offer published on the CNRS job portal
Description of the thesis topic:
PICOSECOND LIBS AND INFRARED SPECTROSCOPY CHARACTERIZATION OF THE STORAGE OF HYDROGEN IN ZEOLITES
The reversible storage of hydrogen in solids is a major challenge in boosting the use of new carbon-free forms of energy necessary for the energy transition (energy vector, transport, etc.). In this context, the use of zeolites is particularly promising.
To determine the efficiency of reversible storage, it is essential to be able to accurately measure the hydrogen charge, particularly in situ, a determination which remains difficult in general.
The project, in which the planned thesis works, is intended to measure by Laser-Induced Breakdown Spectroscopy (LIBS at CORIA, UMR located in Saint-Etienne du Rouvray) the hydrogen concentration in zeolites, a concentration verified by infrared spectroscopy (preparation of zeolites and infrared spectroscopy performed at LCS, UMR located in Caen). This measurement requires the experimental determination of the parameters of the induced plasma and the estimation of the deviation from the local thermodynamic equilibrium. It therefore presents a strong fundamental aspect. These parameters will allow the use of the CORIA simulation codes and the determination of the experimental conditions most relevant to precise in situ measurements.
The PhD student will be in charge of a large part of the experimental study of the project, that which is primarily intended to determine the deviation from the local thermodynamic equilibrium of the plasma. In addition, he/she will liaise between the CORIA and LCS teams by participating in the preparation and infrared characterization of zeolites at LCS and in the study of laser-induced plasmas produced on these zeolites at CORIA.
1. Preparation and infrared characterization of zeolites at LCS, Caen – Firstly, the PhD student will participate in the preparation of the zeolites required for the project, as well as their characterization by infrared spectroscopy. The strong affinity for water of this type of material requires compliance with a strict protocol in which the doctoral student will be trained. The experience he/she will have thus acquired will allow him/her (1) to be able to prepare samples whose hydrogen content will be different and controlled and (2) to handle as best as possible the samples which will be brought to CORIA for the second phase of the study.
2. Determination of the hydrogen concentration of samples by LIBS at CORIA, Saint-Etienne du Rouvray – Secondly, the doctoral student will use the PLEIADES platform of the CORIA laboratory to produce laser-induced plasmas used during the LIBS diagnostics in a hydrogen-free environment on samples prepared at LCS. He/she will have to measure the electron density and temperature fields of the plasma and their changes over time. This determination will be based on spectroscopic analysis of the [120, 800] nm range including VUV. By analyzing in detail the lines of hydrogen (Lyman and Balmer series), he/she will determine its concentration, which will be verified by calculation, according to the deviation from the local thermodynamic equilibrium of the plasma. Different codes developed at CORIA will be used to this purpose.
The doctoral student will thus achieve a very original expertise focused on the implementation and on the use of different complementary types of spectroscopy.
The « Centre National de la Recherche Scientifique » CNRS is a public multidisciplinary research institution placed under the supervision of the French Ministry of Higher Education, Research and Innovation. The CNRS is one of the most important research institutions in the world. To meet the major present and future challenges, its scientists are exploring living things, matter, the universe and the functioning of human societies. Internationally recognized for the excellence of its scientific work, the CNRS is a benchmark both in research and development and for the general public. The proposed thesis will take place within one of its UMR (Unité Mixte de Recherche) and will be attached to the ED 591 PSIME doctoral school (Physics, Engineering Sciences, Materials, Energy). It will take place at CORIA (Complexe Interprofessionnel en Aérothermochimie) UMR 6614, Saint-Etienne du Rouvray (scientific campus of the University of Rouen-Normandie) in the “Physico-chemistry of plasma media” team under the direction of Drs. Arnaud Bultel and Vincent Morel.
The team operates a complete platform for the production and studies of laser-induced plasmas based on the use of pico- and nanosecond laser sources and the most efficient means of analysis in terms of spectroscopy (emission, absorption, fluorescence, diffusion) and visualization (ombroscopy, strioscopy) resolved in time (around 1 ns) and in space (around 3 µm). The team also has all the means to model and simulate the dynamics of the plasmas generated and their radiative characteristics.
The work will be carried out in collaboration with the Laboratoire Catalyse et Spectrochimie (LCS, UMR 6506) in Caen on the LCS vibrational spectroscopy platform under the supervision of Drs Françoise Maugé, Philippe Bazin and Alexandre Vimont.
Constraints and risks:
The proposed work will require stays at LCS in Caen to prepare the relevant samples and characterize them by infrared spectroscopy. Most of the experimental work will take place in Saint-Etienne du Rouvray.
Much of this work relies on the use of Class IV laser sources. Training in the dangers, risks and uses of these laser sources must take place before all experimental work.
The young researcher should hold a master’s degree in energy (or an engineering degree) oriented towards optical diagnostics, in particular spectroscopic, with knowledge of laser sources. The candidate must have an openness that will allow him/her to lead a project in a multidisciplinary context. He/she should also show a clear editorial quality as well as be able to formulate and lead a scientific project, to work in a team while demonstrating autonomy and organizational capacity.
Interested candidates must provide a complete CV mentioning two reference persons likely to be contacted by recruiters, the title and summary of their M2 internship, the grades obtained at M1 and M2 levels as well as a motivation cover letter.
Deadline for receipt of applications: June 30, 2021