Fabrication of an innovative designed TiO2 nanosheets/CdSe/polyaniline/graphene quaternary composite and its application as in-situ photocathodic protection coatings on 304SS

Abstract In this paper, an innovative designed TiO2 nanosheets/CdSe/Polyaniline/Graphene (TCPG) quaternary composite was fabricated in order to improve the efficiency of photoelectron conversion and transmission. Then, by mixing TCPG with epoxy resin (ETCPG), in-situ coatings have been developed and prepared to realize photocathodic protection for 304 stainless steel(304SS). Compared to bare TiO2 nanosheets and bare 304SS, the ETCPG coating exhibited remarkable photoelectrochemical properties, such as the photocurrent density increased 6.8 times to 340 μA/cm2 and the corrosion potential shifted from −408mV to −844mV respectively. Furthermore, the photocathodic protective performance of the coatings could last for at least 4 h in the dark condition, which showed excellent stability, energy storage and potential application. The synergistic effect between the extension absorption in the visible region and the efficient separation of electron-hole pairs improved the photoelectrochemical performance. The photocathodic protective mechanism was attributed to the shift of Fermi-level, which led the system achieved higher electric field strength in the semiconductor heterojunction interface, driving the electrons to flow directly to the substrate.