Co3O4/CdS energy-storing nanocomposite: A promising photoanode for photoelectrochemical cathodic protection in the dark

In this paper, a bi-layered Co3O4/CdS photoelectrode was prepared for photoelectrochemical cathodic protection (PECP) of 304 stainless steel (SS) and Q235 carbon steel (CS). The nanoporous Co3O4 was prepared from a Co-MOF precursor using a template method, which endows Co3O4 with more active sites for redox reaction, good charge carrier migration capability, and excellent energy storage capacity. CdS nanoparticles were used as sensitizer and were deposited on the surfaces of Co3O4 using successive ion layer adsorption and reaction (SILAR) method. The results showed that Co3O4/CdS photoelectrode could provide a time-delay cathodic protection for both 304 SS and Q235 CS in the dark, satisfying the cathodic protection potentials of both metals in industry.