PhD student (M/F) in molecular chemistry and electrochemistry: cobalt catalysts with macrocyclic ligands for proton and CO₂ reduction.2.

Job Description

Thesis Subject

The development of artificial photosynthesis systems for water splitting and CO₂ reduction, aimed at producing hydrogen as an energy carrier and value-added chemicals such as CO and formic acid (HCOOH), requires efficient, selective, and robust catalysts. These catalysts must operate at low overpotentials, exhibit high turnover numbers (TONs) and frequencies (TOFs), and be based on earth-
abundant transition metals. Despite challenges related to long-term stability, molecular catalysts offer major advantages over inorganic systems, including well-defined structures, identifiable active sites, and detailed insight into catalytic mechanisms in homogeneous solution. In addition, ligand design enables fine control over catalytic efficiency and product selectivity, particularly for the CO₂ reduction
reaction (CO₂RR). However, further improvements in catalytic performance toward efficiencies approaching those of metalloenzymes require modulation of the second coordination sphere (SCS). Hydrogenases and carbon monoxide dehydrogenase (CODH) can indeed reversibly catalyze proton reduction to H₂ and CO₂ reduction to CO at high rates, near thermodynamic potentials, and in neutral water, owing in large part to SCS effects.
In this context, this thesis aims to develop a still underexplored yet highly promising family of cobalt catalysts featuring tetra-aza macrocyclic Schiff-base ligands incorporating a pyridyldiimine motif, known for their activity in both the hydrogen evolution reaction (HER) and CO₂RR.
The proposed approach relies on targeted ligand functionalization to introduce second-sphere effects that promote proton transfer and/or stabilize metal intermediates. The new complexes will be studied in homogeneous solution by electrochemical and spectroscopic methods (UV-Vis/NIR, EPR). Their excellent electrocatalytic performance for HER and CO₂RR, in terms of efficiency, selectivity, and robustness, will be evaluated by cyclic voltammetry and electrolysis. Our systematic approach toward increasingly sophisticated systems will provide a unique opportunity to obtain relevant information on the influence of the microenvironment (second coordination sphere) on the catalytic activity of molecular complexes in the homogeneous phase, with the aim of achieving a comprehensive understanding of catalysis beyond the first coordination sphere.
The PhD student will be in charge of the study of the electrochemical and spectroscopic studies of the new cobalt complexes in homogeneous solution, their electrocatalytic properties for protons reduction and CO2 reduction (Molecular Electrochemistry and Redox Photochemistry (EMPRe) team at the Department of Molecular Chemistry (DCM)). The PhD student will also participate in the synthesis and characterization of new complexes. This project is part of a collaboration with the Synthesis and Reactivity in Organic Chemistry (SeRCO) team at DCM, a partner in the ANR InnovMat project. The SeRCO team, expert in organic synthesis, will be responsible for the organic synthesis of ligands substituted with various functional groups.
Methods and Techniques :
• Coordination chemistry: synthesis and characterization of new cobalt complexes (inorganic synthesis, mass spectrometry, structure determination by X-ray diffraction)
• Molecular electrochemistry (cyclic voltammetry, electrolysis, electrocatalysis) and spectroscopy (UV/Vis, EPR, IR)
• Analysis of reduction products by gas and liquid phase chromatography
Profile and skills required.
The candidate should hold a master's degree in chemistry with interest for coordination chemistry, molecular electrochemistry and small molecules activation. Experience in electrocatalysis will be appreciate.

Your Work Environment

The PhD work will be carried out within the EMPRe team (https://dcm.univ-grenoble-alpes.fr/research/electrochimie-moleculaire-et-photochimie-redox) at the Department of Molecular Chemistry (DCM), located on the campus of Université Grenoble Alpes. The DCM (https://dcm.univ-grenoble-alpes.fr/departement-chimie-moleculaire) is a joint research unit of CNRS/Université Grenoble Alpes (UGA), organized into 6 thematic teams with approximately 150 members. Its scientific focus addresses major societal themes: health and well-being, and new energies, in addition to fundamental aspects. This work is part of a collaboration with the SERCO team at DCM (https://dcm.univ-grenoble-alpes.fr/research/synthese-et-reactivite-en-chimie-organique) (partner of the ANR InnovMat project), which is responsible for the organic synthesis of new ligands.
Within the EMPRe team, we develop and analyze electrochemical and photoinduced redox catalytic processes in homogeneous solution and on surfaces. EMPRe team students are trained in the synthesis of ligands and transition metal complexes. They then apply methods of molecular electrochemistry (cyclic voltammetry, electrolysis), spectroelectrochemistry, and surface modification (electropolymerization, electrodeposition) to study the mechanisms of electro/photocatalytic processes. In this context, we particularly study the activation of small molecules (such as H₂O, CO₂, N₂O) as well as proton-coupled electron transfer processes.
The EMPRe team has all the necessary equipment for electrochemistry experiments under inert atmosphere (argon glovebox coupled with a UV/Vis/IR spectrophotometer) and electrocatalysis, as well as for the quantification of H₂ and CO₂ reduction products by chromatography (gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography (HPLC)). Some characterizations and analyses will be carried out via the platforms of the Grenoble campus laboratories: the Institut de Chimie Moléculaire-ICMG for NMR spectroscopy, mass spectrometry (MS), X-ray diffraction, and EPR.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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