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

In this paper, an innovative designed TiO 2 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 TiO 2 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. Image 1 • Enhanced photoeletric performance was obtained by a novel designed TCPG composite. • An in-situ photocathodic protective coating was first developed by TCPG composite. • The corrosion potential of 304SS was shifted from −408mV to −844mV by this coating. • The synergistic mechanism promotes photoelectric conversion efficiency remarkably. • The controlled Fermi level shift drives the photoelectrons flow directly to 304SS. [ABSTRACT FROM AUTHOR]