Efficient photocathodic protection enabled by a multi-dimensional quaternary hybrid superstructure

The global annual steel waste associate with interface corrosion represent significant challenges for steel's lifetime as well as sustainable development of modern society. Herein, we report a unique multi-dimensional quaternary hybrid superstructure for photocathodic protection (PCP) which not only has an intense visible to near-infrared absorptivity for generating 'hot' electrons but also can provide time-delay anti-corrosion functions in the dark. We exemplified the PCP performance of this quaternary composite on a typical 304 stainless steel (304SS) which results in its surface potential shifting negatively by about 660 mV compared to its natural corrosion potential under visible light illumination. Besides, time-delay protection without illumination is also demonstrated, which is resulted from the "electron pool" effect associates to the embedded zero-dimensional quantum dots. Based on density functional theory (DFT) simulations as well as comprehensive electron microscopy studies, we elucidate the origin of the enhanced PCP performances are attributed to the improved work per photon using 'hot' carriers, which surpass the limit of the state-of-the-art PCP technologies. In addition, we found the use of one-dimensional titanium dioxide nanorods and two-dimensional reduced graphene oxide as a scaffold can structure the metal nanoparticles and forces photoinduced 'hot' electrons to transfer to the functionalized 304SS. Various promising functionalities arises from the use of as-proposed multi-dimensional quaternary superstructure as a sustainable anti-corrosion material can be envisioned.