Usually, photocorrosion is interpreted on the basis of energy schemes, comparing the quasi-Fermi levels of charge carriers to the corrosion potentials of the photoelectrode [2]. However, the competition between the pure redox process of water splitting and photoelectrode dissolution/passivation can be highly influenced by kinetic parameters [3].
We use a physics-based model to study photocorrosion phenomenon in monolithic photoelectrochemical devices. The studied device is composed of different catalyst covered semiconductors, immersed in a liquid electrolyte. Acidic and alkaline conditions are tested. The catalyst layer is considered a nanoporous media, the solid phase being composed of a supporting structure and catalyst particles. Accurate thermodynamic and kinetic measurements on different semiconductor/catalyst/electrolyte combinations support our study. These measurements include rotating ring-disc measurements, cyclic voltammetry and chronoamperometry. The simulation results show how irradiation intensity, kinetic parameters, and mass transport in the two-phase flow can impact the stability of the photoelectrode/electrolyte interface.
[1] F. Nandjou and S. Haussener. Degradation in photoelectrochemical devices: Review with an illustrative case study. J. Phys. D: Appl. Phys. 50 (2017) 124002.
[2] Gerischer H, et al. Report EUR 9531 EN (1984), Commission of the European Communities.
[3] R. Memming. The Role of Energy Levels in Semiconductor‐Electrolyte Solar Cells. J. Electrochem. Soc. 125 (1978) 117.