Description du sujet de thèse

Photo-electrocatalytic materials based on earth abundant elements, such as Fe and Ni-based transition metal oxides, offer a great opportunity to generate renewable fuels, and chemicals that replace fossil fuels. However, increasing the efficiency and selectivity of these reactions remains a big challenge. The problem is that we do not understand the surface reactivity in these materials and we need better understanding of the catalytic cycles.

During a (photo)electrochemical reaction, multiple reactive intermediates are generated at the surface of the material. The energetics and interaction of these intermediates with other species in the medium or with defects in the solid ultimately dictate the outcome of the reaction. Traditionally, it has been difficult to study these intermediates. However, recent advances in spectroscopy offer the opportunity to visualise active species with unprecedented precision. Moreover, coupling such advances with new optical tools may even allow us to control the reaction mechanisms on demand.

This thesis will develop new spectroscopic tools to identify reaction intermediates during (photo)electrochemical transformations and construct mechanistic models of reactivity. The candidate will also implement new methods aimed at controlling the interactions between intermediates and changing the reaction mechanism and product selectivity.

This PhD project is at the interface between physics and chemistry as it will apply advanced spectroscopy and optical modulation tools to probe chemical systems currently being explored for energy conversion applications. The materials studied will primarily be metal oxides that can drive oxidation reactions such as the oxidation of organic compounds to generate added-value chemicals or the water splitting reaction. This thesis will rely on (photo)electrochemical, crystallography and spectroscopy equipment available in Rennes. Moreover, it is likely that experimental time at large-scale facilities, such as synchrotrons and X-ray free-electron lasers, will also be needed.

Contexte de travail

We look for a very motivated candidate interested in working in a highly collaborative environment. The candidates should have basic knowledge and a desire to deepen their understanding in the fields of materials science, (photo)electrochemistry, as well as crystallography and spectroscopy. They should be familiar with various experimental techniques such as spectroscopy (optical or X-ray). It is desirable for candidates to be acquainted with data processing programs (such as Python or similar) and be interested in developing experiments at large-scale facilities.

Contraintes et risques

The candidate will be working at the CNRS and specifically associated to the Materials and Light Department at the Institute of Physics of Rennes. We are a highly collaborative and international team with more than 20 researchers working in the areas of ultrafast spectroscopy, crystallography and energy conversion. Our research facilities include 4 ultrafast lasers, 2 diffraction spectrometers, sample deposition equipment as well as electrochemical capabilities. Our group has received funding by the ERC, the ANR or Rennes Metropole and the Department leads the CNRS international lab DYNACOM in partnership with the University of Tokyo.

Informations complémentaires

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