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Reference : UPR8001-ALAEST-004
Workplace : TOULOUSE
Date of publication : Monday, April 26, 2021
Scientific Responsible name : ESTEVE Alain
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 September 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
The thesis is focussed on the generation of new photocatalytic surfaces for the production of green hydrogen by photocatalysis (watter splitting).
In a first axis, we will increase the effective contact surface between the substrate and the liquid medium. We will rely on current technologies (PVD in particular, deposited on TiO2) for demonstration: establishing a relationship between hydrogen production and specific surface / liquid contact surface. We will search for surface structures maximizing the specific surface area taking into account the limitations of PVD in conformational layers on surfaces with aspect ratios. Thus, in a second step, we will make use of the ALD technique (Atomic Layer Deposition), where the deposition of conformal layers can be carried out on surfaces presenting very important aspect ratios or even mesoporous materials.
The second axis will aim to increasing the coupling of 2-photon electronic effects to maximise synergistic effects between the photo-charges induced in the semiconductor and the plasmon field of metal nanoparticles in inclusion in the semiconductor. To do so, we will use a semiconductor with nonlinear optical properties, such as BaTiO3 which presents interesting characteristics at many levels for photocatalysis: cost, chemical resistance, properties close to our TiO2 reference in terms of gap and band alignment with the hydrogen reference ... This choice will allow a simpler comparative evaluation with our current data of TiO2-based photocatalysts. The work will have to validate the realization of an Au nanoparticle hybrid structure buried in the microstructured BaTiO3 layer and quantify / validate a gain in hydrogen production compared with our current devices.
The deployment of clean energies is an essential axis of the energy transition. In this context, the use of hydrogen is a reality today, but its potential still requires new technological innovations. This is true for its production, which is mainly operated from fossil fuels. The proposed work focuses on the use of innovative materials for the production of hydrogen by decomposition of water molecules via solar radiation. These materials must be structured at the nanometric scale (both on aspects of the architecture of the matter and on the distribution of heterogeneous chemical species) in order to optimize the synergy of the many microscopic mechanisms involved to ensure the water-hydrogen conversion.
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