Fe/TiO2 composite coatings modified by ceria layer: Electrochemical synthesis using environmentally friendly methanesulfonate electrolytes and application as photocatalysts for organic dyes degradation

•Fe/TiO2 composites modified by electrodeposition of ceria layer.•Application of methanesulfonate electrolytes for electrodeposition.•Enhanced corrosion resistance resulted from modification of Fe matrix by CeO2 film.•Photocatalytic activity of Fe/TiO2, CeO2 composites in reactions of dyes degradation.

This work reports the results of our effort to manufacture Fe/TiO2 electrodeposited composite coatings modified by ceria layer and use them as heterogeneous photocatalysts for the decomposition of some organic dyes. Iron electrodeposited matrix may be a cheap, available, nontoxic and easily repairable support for TiO2 photocatalysts, however, it is not corrosion-resisting enough. In order to improve the corrosion stability, as-deposited Fe/TiO2 (5% wt. of titania) composite coatings obtained from a methanesulfonate iron plating bath were modified by cathodic treatment in solution containing cerium (III) methanesulfonate. As a result, a very thin layer of cerium oxides was formed on the surface of Fe matrix. The corrosion resistance of iron/titania coatings after their modification by ceria film was studied by means of voltammetry method and electrochemical impedance spectroscopy. The surface modification of Fe/TiO2 composites by ceria layer resulted in a significant increase in their corrosion stability which allows their practical application as photocatalysts for wastewater treatment. The photocatalytic properties of TiO2 particles immobilized on Fe/TiO2 composite electrodeposits modified by ceria layers were tested in the reaction of photochemical degradation of methyl orange (MO) and methylene blue (MB) dyes in water under the action of UV radiation. The apparent rate constants of MO and MB photodegradation at natural pH values were 0.0018 and 0.0056 min−1, respectively. Thus we developed a new technique of TiO2 particles immobilization for advanced oxidation processes, which involves electrodeposited composite coatings with Fe matrix.