On Thursday 17 December at 9:30 am, Ms Caroline Supplis will publicly and remotely defend her PhD thesis entitled:
"Modelling and experimental study of solar hydrogen production in a photoreactor"
Link : https://us02web.zoom.us/j/86862507446?pwd=VmVMQ0tiMGo3U2xWK3pGM0lhQmNBdz09
Meeting ID: 868 6250 7446
Passcode: 185713
The work will be presented to the following jury:
- Cyril Caliot (Rapporteur)
- Karine Loubière (Rapporteur)
- Murielle Chavarot-Kerlidou (Examiner)
- Frédéric Gloaguen (Examiner)
- Gaël Plantard (Examiner)
- Jean-François Cornet (Thesis Director)
- Jérémi Dauchet (Co-supervisor)
- Fabrice Gros (Co-supervisor)
ABSTRACT
As part of the energy transition, converting solar energy into fuels suitable for mobility appears to be a promisingsolution. One of the first accessible is undoubtedly hydrogen, which can be obtained by photodissociation of the water molecule
under the effect of radiation absorbed by a photocatalytic system. This mechanism is known as artificial photosynthesis. The
challenge is serious because it is necessary to find effective and inexpensive chemical systems but also to design, develop and
optimize the photoreactive processes implementing these reactions, in the long term on a large scale. This last objective can only
be achieved in a reasonable time if we have predictive and generic models that integrate the physical phenomena describing the
underlying scales having an impact on the observables of the process.
This work is concerned with the modeling of a photoreactor limited and controlled by photon transport implementing
photocatalytic systems for the production of solar hydrogen as well as its experimental validation. The model begins with the
determination of the optical and radiative properties of the studied photocatalytic system which falls under electromagnetism.
Then, solving the Radiative Transfer Equation (RTE), with elastic or inelastic scattering depending on the practical case, provides
access to the local volumetric rate of photons absorbed within the photoreactor. Finally, the formulation of a thermokinetic
coupling law and an average on the scale of the reactor make it possible to determine the observables which are the average
volumetric rate of hydrogen production and energy efficiency. An optical bench equipped with an integrating sphere allows
experimental validation of the radiative properties. A study bench composed mainly of LED light sources and a gas tight planar
photoreactor filled with a photoreactive medium provides access to experimental observables via a measurement of the pressure
in the gas headspace of the reactor for several flux incident photon flux density values and photocatalyst concentrations. The
model is then used to identify from the experiments a single lumped parameter for the kinetic constants of the reaction. Two
photocatalytic systems representative of the diversity of systems studied in the literature have been implemented: 1) a molecular
system with a bio-inspired catalyst for protons reduction in homogeneous phase and 2) a system based on micrometric particles of
CdS (semiconductors) with or without MoS2 cocatalyst in heterogeneous phase.
The model ultimately makes it possible to study and optimize various engineering parameters determining the kinetic and
energy performances of the photoreactive process, depending on its geometry and the solar operating conditions. The possibility
of achieving very significant energy efficiency gains by developing photoreactors with internal radiation dilution is highlighted.