TiO₂−WO₃ Photoelectrochemical Anticorrosion System with an Energy Storage Ability

TLDR

TiO₂ coatings protect metals by generating reductive energy under UV, and coupling them with WO₃ creates an electron‑pool that can store this energy. On a 304 stainless steel plate, a WO₃ film is charged by a UV‑irradiated TiO₂ coating in 3 wt % NaCl solution at pH 5. The charged WO₃ layer shields the steel even after UV is off, enabling repeatable day‑night protection and similar performance with a TiO₂–WO₃ composite coating.

Abstract

TiO2 coatings are known to protect some metals, including type 304 stainless steel, from corrosion on the basis of its reductive energy generated under UV irradiation. A TiO2 coating is coupled with a WO3 coating as an electron 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 coating 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 coating protects the plate during the night. The charge−discharge cycles are repeatable. A TiO2−WO3 composite coating also has the same effects.