Zn<sub>3</sub>In<sub>2</sub>S<sub>6</sub>/TiO<sub>2</sub> Nanocomposites for Highly Efficient Photocathodic Protection to Carbon Steel
Shouwu Xu, Kaili Zhang, Lili Du, Daming Gong, Guiwu Lu, Ping Qiu
Abstract
Photocathodic protection has evoked great attention in stainless steel protection; however, it has not been fully studied on carbon steel. This study has prepared a series of TiO2/Zn3In2S6 nanocomposite films by combining anodic oxidation with hydrothermal methods, in which composition and morphology together with optical properties have been characterized. This heterojunction TiO2/Zn3In2S6 has allowed access to visible-light absorbance. Photoelectrochemical tests suggest that this film can supply effective photocathodic protection to carbon steel. The maximum photogenerated potential drop achieved on TiO2/Zn3In2S6-30 coupled to carbon steel is about −0.49 V even after 80 h of illumination, and the corresponding photocurrent is 1.91 mA·cm–2, which is about 5 times higher than that of pure TiO2. This is benefited from the effective photogenerated charge separation by the built-in electric field in the heterojunction. The detailed mechanism has been discussed in the paper.