Design of a One-Dimensional Zn3In2S6/NiFe2O4 Composite Material and Its Photocathodic Protection Mechanism Against Corrosion

Z-scheme Zn3In2S6/NiFe2O4 nanocomposites were prepared by electrospinning and hydrothermal methods, and their photocathodic protection performance was studied on 304 SS and Q235 CS in NaCl solution (3.5 wt.%). The two-dimensional Zn3In2S6 loaded on the one-dimensional NiFe2O4 resulted in faster electron migration and enhanced light absorption capability. Moreover, it had been observed through electrochemical testing that the assembly of Zn3In2S6/NiFe2O4 heterojunctions improves the efficacy of photocathodic protection. Following illumination, the self-corrosion potentials of 304 SS and Q235 CS coupled with Zn3In2S6/NiFe2O4 nanocomposites decreased by 1040 mV and 560 mV, and the photoinduced current densities were 1.2 times and 3.9 times greater than the value of Zn3In2S6. Furthermore, the mechanism of enhanced photocathodic protection performance for Zn3In2S6/NiFe2O4 heterojunctions was systematically discussed. XPS and ESR analysis indicated that Zn3In2S6/NiFe2O4 composites follow the Z-scheme electron migration path and retain the stronger reduction and oxidation capacity of Zn3In2S6/NiFe2O4. Therefore, the Z-scheme heterostructures are responsible for the realization of cathodic protection for carbon steel.