Glutathione-sensitized SnS2 nanoflake/CdS nanorod heterojunction for enhancing cathodic protection of 304 stainless steel with remarkable photoelectric conversion performance

An effective way to enhance photochemical performance can be achieved by optimizing the microstructure of composite semiconductor materials. Here, a two-step hydrothermal method was used to synthesize SnS2/CdS composite photoanodes for photocathode protection applications, and glutathione was introduced as a structure-directing agent to enhance the separation efficiency of photogenerated electron-hole pair of SnS2/CdS. In the presence of glutathione, SnS2 became a smaller and thinner nanoflake and hexagonal CdS extended into a rod shape, the combination of them resulted in larger light collection area and higher charge transfer rate. The electrochemical test results demonstrated that the open circuit potential of 304 SS coupled with SnS2/CdS/GSH photoanode was negatively shifted to about −0.5 V under light, which not only far exceeded the self-corrosion potential of 304 SS (-0.18 V), but also improved from −0.42 V of SnS2/CdS. Further, the photogenerated current density of SnS2/CdS/GSH was nearly three times that of SnS2/CdS, EIS and polarization curve results also indicated that glutathione enhances the PEC performance of SnS2/CdS. Obviously, the type-II heterojunction formed by glutathione-sensitized SnS2/CdS provides more electrons for 304 SS, which is beneficial to achieve better photocathodic protection.