Sujet de stage / Master 2 Internship

The topic of this internship is part of the theme: hydrogen production by solar water splitting. In particular, we are interested in optimizing iron oxide-based photoanodes to increase the efficiency of the photoelectrolysis reaction. The aim is to use scanning electrochemical microscopy (SECM) to measure and characterize electrochemical activity relative to the oxygen evolution reaction (OER) at the local level of nanostructured hematite-based photoanodes.

The aim of this internship is to measure and characterize electrochemical activity relative to the oxygen evolution reaction (OER) at the local level of nanostructured photoanodes based on hematite (Ti:Fe2O3) catalytically activated by oxyhydroxide structures (M-OOH where M = Fe, Co or Ni) using the scanning electrochemical microscopy (SECM). The images obtained with the SECM will be correlated with the macroscopic photocurrent obtained during a photoelectrolysis experiment. Additional measurements will be realized by electrochemical impedance spectroscopy (EIS) in order to characterize and model the photoanode/electrolyte interface.

During the internship, the student will carry out the aqueous chemical growth of photoanodes at the SPEC laboratory. This type of growth will allow us to obtain a very particular morphology of photoanodes, carpet-like morphology where the nanorods are perpendicular to the substrate. The student will use the solar water splitting dedicated setup at the SPEC laboratory to make photoelectrochemical measurements (photocurrent and EIS). Electrochemical microscopy measurements will be performed using the PF-SECM (Peak Force Scanning ElectroChemical Microscope) at ICMMO laboratory. This study will allow us to correlate the local aspects (nanorods morphology, local electrochemistry) with the macroscopic ones (photocurrent, interface characterization of the by EIS: flat band potential, carriers’ concentration, surface states, etc.). Complementary physico-chemical characterizations (MEB, DRX, XPS) are also envisaged.

References:
1. Walter, M. G., Warren, E. L., McKone, J. R., Boettcher, S. W., Mi, Q., Santori, E. A. & Lewis, N. S. Chem. Rev. 110, 6446–6473 (2010).
2. Fujishima, A. & Honda, K. Nature 238, 37–38 (1972).
3. Van De Krol, R. & Gratzel, M. International Journal of Renewable Energy Research vol. 2 (Springer, 2012).
4. Vayssieres, L. Int. J. Nanotechnol. 1, 1–41 (2004).
5. Stanescu, D., Piriyev, M., Villard, V., Mocuta, C., Besson, A., Ihiawakrim, D., Ersen, O., Leroy, J., Chiuzbaian, S. G., Hitchcock, A. P. & Stanescu, S. J. Mater. Chem. A 8, 20513–20530 (2020).

Techniques: AFM, SECM, MEB, DRX, XPS, EIS, (photo-) voltammetry, aqueous chemical growth

Qualities and skills required for the candidate: M2 student, knowledge of electrochemistry, (photo-) catalysis, physics of semiconductors. For data processing and redaction of the internship report: office, python.