A comparison of water photo-oxidation and photo-reduction using photoelectrodes surface-modified by deposition of co-catalysts: Insights from photo-electrochemical impedance spectroscopy. (19th April 2019)

• Record Type: Journal Article
• Authors: Antuch, M.; El Rouby, W.M.A.; Millet, P.
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 20(2019)
• Page Start: 9970
• Page End: 9977
• Publication Date: 2019-04-19
• Subjects: Water photo-oxidation -- Water photo-reduction -- Titanium dioxide nanorods -- Strontium titanate -- ZIF-67 MOF; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.11.214
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The purpose of this research paper is to highlight the similarities in the kinetic treatment between water photo-oxidation into molecular oxygen and water photo-reduction into molecular hydrogen, using photoelectrodes surface modified by deposition of co-catalysts. Photo-anodes made of TiO2 nanorods surface-covered by crystals of cobalt Zeolitic Imidazolate Framework (ZIF-67), and photo-cathodes made of Rh:SrTiO3 particles surface-modified by adsorption of molecules of trisdioximate hexa-chlorine cobalt (II) clathrochelate (Co(Cl2 Gm)3 (BCH3 )2 ), have been prepared and used for water photo-oxidation and photo-reduction experiments, respectively. Both photoelectrodes have been characterized by SEM and cyclic voltammetry under illumination conditions. Charge transfer mechanisms have been investigated by photo-electrochemical impedance spectroscopy (PEIS). It is shown that for both systems, the presence of a co-catalyst increases the charge transfer kinetics, and that the trapping resistance is larger than the charge transfer resistance, at any operating potential. Highlights: Water photo-oxidation on titanium dioxide with Zeolitic Imidazolate Framework. Water photo-reduction on strontium titanate with cobalt clathrochelate. The mechanisms are analyzed by photo-electrochemical impedance spectroscopy. Data are modeled by taking into account surface trapping of charge carriers. Microscopic rate parameters of the two systems are compared.