Review on the Solar-Driven Photocathodic Protection of Metals in the Marine Environment

Photocathodic protection (PCP) technology has gained wide attention in the field of corrosion due to its green, environmentally friendly, and sustainable characteristics, and has become a protection technology with broad development prospects in the future marine environment. By investigating recent research results, the mainstream photoanode materials are TiO2, BiVO4, g-C3N4, ZnO, In2O3, SrTiO3 and other materials. Among them, TiO2 is an ideal photoanode material for PCP because of its efficient photochemical corrosion resistance, remarkable reaction stability, and excellent photoelectric properties. However, TiO2 itself has more drawbacks, such as limited utilization of visible light and low photogenerated electron-hole separation efficiency. These defects limit the wide application of TiO2 in PCP. Through modification methods, the reaction efficiency can be substantially improved and the availability of TiO2 can be increased. This paper lists the research progress of modifying TiO2 materials using metal and non-metal doping modification, semiconductor compounding technology, and energy storage materials for application in PCP, and introduces several new types of photoanode materials. This paper suggests new ideas for the design of more efficient photoanodes.