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Reference : UMR5306-LUKMAC-002
Workplace : VILLEURBANNE
Date of publication : Friday, July 2, 2021
Scientific Responsible name : Luke MacAleese
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Study, between molecular physics, analytical and catalytic chemistry, of the structure and photo-catalytic activity of molybdenum clusters in view of applications for environment, sustainable energy and CO2 recycling.
The environmental emergency sets us in front of the utmost necessity to reduce drastically CO2 emissions. Two directions have to be explored simultaneously: (1) produce decarbonated storable (chemical) energy, such as H2 generated by water photolysis (2) sequester CO2, e.g. by reduction into methanol. Both of these reactions can be photo-catalyzed by molybdenum clusters[1,2]: cheap and relatively earth-abundant, they may provide a widely distributable solution.
This research project aims at contributing to the pressing need for fundamental research towards at green chemistry and sustainable energy in a field where “there is usually more speculation than true knowledge about the mechanisms of catalytic processes” and “the identity of the catalytically active species is frequently not known”. The challenge is to understand the elementary steps in these photo-catalytic cycles in order to propose a robust and efficient catalyst beyond the proof of principle.
Octahedral Mo6 photo-catalyst clusters will be prepared by our partners from ISCR in Rennes (synthesis and quantum chemistry). At iLM, ion trap approaches will be undertaken[4,5]. These are particularly relevant to study reactivity in homogeneous catalysis since reagents are “molecular” systems that can be isolated from reactive media by mass spectrometry. Once in the gas-phase, the specific reactivity of these systems towards gaseous reagents (CO2, H2O,...) and under irradiation will be probed individually.
POSITION AND RESEARCH PROGRAM:
The initial stage will be dedicated to the implementation of two new experimental setup:
• the first setup enables the analysis, by mass spectrometry, of the chemical composition of reactive solutions under controlled irradiation;
• the second setup enables the fine control of ion-molecule reactions on reactive intermediates selected and isolated in the ion trap.
In parallel, a wide range of analytical approaches (well established in the lab) will be applied to caracterize intrinsic properties of detected ions (catalysts and intermediates, on the basis of Mo clusters provided by ISCR):
• optical properties (with time resolution when needed) by action spectroscopy
• chemical composition and structure of ions by collisional activation and fragmentation (tandem MS)
• structure and conformation of the clusters by ion mobilities.
Finally, the reactivity of catalysts and intermediates extracted from the reactive solutions will be tested towards H2O, CO2 and other putative reagents by ion-molecules reactions in the gas phase and under irradiation.
The project aims at understanding step-by-step the mechanism of the two reactions under study: water photolysis and CO2 photo-reduction. In order to achieve these goals, the observations and ion characteristics determined at iLM (optical spectra, structure, reactivity) will be shared with the chemists at ISCR where hypotheses will be tested by modelling the reaction process and by alternative syntheses resulting in new generations of catalysts.
Travel and visit at our ISCR collaborators will be organized.
Master in physics and/or chemistry. Specialization in coordination chemistry/catalysis may be relevant in view of the project.
The candidate shows a true ability to adapt to a multidisciplinary context: he/she is ready to dive into and tackle questions related to instrumentation, optics, spectroscopy, chemistry/reactivity and data analysis. The data analysis is performed under Python, thus, knowledge of Python langage is a serious pro.
Curious and resourceful, he/she possesses a sincere taste for effort and personal investment. Rapidly autonomous, he/she knows how to manage his/her project with rigor and efficiency. He/she is not afraid to take initiatives, eager to learn, dedicated and enthusiast at work. Motivated by the project and ready to give account of his/her progress.
Fluency in English.
1 Kumar, P. et al. RSC Adv. 2014, 4 (20), 10420.
2 Feliz, M. et al. ChemSusChem 2016, 9 (15), 1963–1971.
3 Frenking, G. Topics in Organometallic Chemistry (12), Theoretical Aspects of Transition Metal Catalysis, Springer 2005
4 Zavras, A. et al. Nat. Commun. 2016, 7, 11746
5 MacAleese, L. et al. J. Am. Chem. Soc., 2016, 138, 4401–4407.
IN ORDER TO APPLY:
Thank you to join to the application a curriculum vitae, a motivation letter, if possible reference letters as well as the description of one personal project performed in/out of academia.
The PhD will take place in the research group "SpectroBio" of the iLM institute (http://ilm.univ-lyon1.fr/spectrobio). This group (~10 researchers/profs) dedicates to research fields from fundamental physics to applications in biochemistry and analytical sciences with methods coupling laser spectroscopy, imaging, mass spectrometry and ion mobility.
The research group studies in particular the structure, dynamics and reactivity of molecules and nano-objects in controlled environments, as well as their application in catalysis and optical imaging. For that purpose, the group develops his own experimental state of the art tools such as ion mobility, electrostatic storage devices and multiple laser imaging configurations.
This PhD is funded by the research project "PHOTOCAT" granted by ANR.
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