Photocathodic protection of ZnIn2S4/α-Fe2O3 film formed on carbon steel

Purpose This study aims to prepare the ZnIn2S4/α-Fe2O3 nanocomposite films on the surface of carbon steel by combining anodic oxidation and hydrothermal methods, and analyze the morphology, composition, light absorption properties, photoelectric transmission properties and photocathodic protection properties of the composite films. Design/methodology/approach ZnIn2S4/α-Fe2O3 nanocomposite films on carbon steel surface were prepared via the combination of anodic oxidation and hydrothermal methods. The morphology and composition of the films were characterized by relevant characterization techniques, while their light absorption properties were evaluated using corresponding optical testing methods. In addition, electrochemical techniques were used to analyze the photoelectric transmission properties and photocathodic protection properties of the films, with band gap characteristics analyzed based on light absorption data. Findings Via combining anodic oxidation and hydrothermal methods, ZnIn2S4/α-Fe2O3 nanocomposite films were prepared on carbon steel surface. Relevant characterization techniques characterized the films’ morphology and composition; optical testing evaluated light absorption. Electrochemical techniques analyzed photoelectric transmission and photocathodic protection properties, with band gap analyzed based on light absorption data. Originality/value The ZnIn2S4/α-Fe2O3 composite films prepared by the combination of anodic oxidation and hydrothermal methods have a unique “nanoblocks covering nanopores” structure. This structure, combined with the synergistic effect between ZnIn2S4/α-Fe2O3, enhances the light absorption capacity in the visible region, optimizes carrier separation and transmission efficiency, and ultimately achieves a corrosion potential negative shift of over 400 mV for carbon steel. Thus, the composite films exhibit more excellent photocathodic protection performance than single α-Fe2O3 films, providing a new effective approach for carbon steel corrosion protection.