High-efficiency photocathodic protection performance of novel TiO2/ ZnCdS heterojunction films for Q235 carbon steel

Photocathodic protection combines coating and cathodic protection characteristics, representing an innovative anti-corrosion technology. The construction of a heterojunction is an effective approach to enhance the photocathodic protection performance. However, the stability of this approach is often compromised due to semiconductor photocorrosion. In this study, a novel TiO2/ZnCdS heterojunction film was fabricated using anodization and hydrothermal methods. The results demonstrated that the TiO2/ZCS-1 heterojunction film, when coupled with carbon steel, exhibited the most negative open circuit potential of -0.98 V under illumination. Additionally, the photocurrent density reached 0.54 mA & sdot;cm- 2, and the charge transfer resistance was reduced by approximately 20 times compared to TiO2. This improvement can be attributed to ZnCdS's suitable visible light capture bandgap, which enhances the system's resistance to photocorrosion and improves its cathodic protection performance for carbon steel. This research provides valuable insights for developing stable heterojunction films.