A novel TiO2/ZnIn2S4/MgIn2S4 three-phase heterojunction photoanode for enhanced photoelectrochemical cathodic protection of 316L SS

A novel TiO2/ZnIn2S4/MgIn2S4 photoanode for photoelectrochemical cathodic protection (PECCP) was prepared by twostep hydrothermal method. A three-phase multistep heterojunction structure was fabricated by the uniform distribution of ZnIn2S4/MgIn2S4 composite layer on TiO2 nanosheets. The resultant type II heterostructure promoted the separation of photogenerated carriers and alleviated the recombination of electron-hole pairs. A photocurrent density of 34.5 μA cm−2 between the photoanode and 316L stainless steel (316L SS) associated with a potential drop of 587 mV of 316L SS were obtained after coupling the photoanode with 316L SS under the illumination of AM 1.5G, validating a desirable PECCP performance of TiO2/ZnIn2S4/MgIn2S4 photoanode.