In-situ fabrication of TiO2/ZIF-67 composite film with electron storage characteristics for significantly enhanced photoelectrochemical cathodic protection of 304 stainless steel

The development of a photoelectrochemical cathodic protection film with electron storage capabilities offers a feasible method for metal protection in the absence of light. In this study, we designed and fabricated an innovative TiO 2 /ZIF-67 composite film in situ. The synthesized ZIF-67 nanoparticles with a dodecahedral structure not only facilitate contact with the electrolyte but also significantly broaden the sunlight absorption range. When coupled with 304 SS, the TiO 2 /ZIF-67-20 composite film demonstrated a minimum OCP value of −0.675 V (vs. SCE) under illumination. Notably, even after 10 h of light deprivation, the OCP remained lower than that of 304 SS. This sustained protection can be attributed to the electronic storage and release capabilities of the Co element within the TiO 2 /ZIF-67 composite, ensuring continuous cathodic protection for 304 SS during both illuminated and dark conditions. This study contributes valuable insights into achieving all-weather cathodic protection for 304 SS.