TiO2-WO3 photoelectrochemical anticorrosion system with an energy storage ability

TiO2 coatings are known to protect some metals, including type 304 stainles s steel, from corrosion on the basis of its reductive energy generated unde r UV irradiation. A TiO2 coating is coupled with a WO3 coating as an electr on pool, in which the reductive energy can be stored. A WO3 film on a type 304 stainless steel plate can be charged by a UV-irradiated TiO2 coating on the same plate, in a 3 wt % NaCl aqueous solution, PH 5. The charged WO3 c oating can protect the stainless steel plate from the corrosion for a while even after the UV light is turned off. Thus, the TiO2 coating protects the plate and charges the WO3 coating during the day, and the charged WO3 coat ing protects the plate during the night. The charge-discharge cycles are re peatable. A TiO2-WO3 composite coating also has the same effects.