How semiconductor transition metal dichalcogenides replaced graphene for enhancing anticorrosion
Although semiconductor transition metal dichalcogenides (TMDs) are expected to be applied for corrosion protection, few studies have focused on the interactions between TMDs and metal substrates. Herein, few layered TMD nanosheets of MoS2 and WS2 were prepared through a liquid exfoliation technique. And then, the TMD reinforced epoxy (TMD/EP) nanocomposite coatings were fabricated through incorporating MoS2 and WS2 nanosheets into an epoxy matrix. The corrosion behavior of the TMD/EP nanocomposite coatings was investigated by a series of electrochemical tests like EIS and polarization curve tests. And the corrosion-promotion activity of the MoS2 and WS2 was also studied through EIS measurements of the semiconductor/metal contacts at coating defects. Our work reveals that single layered TMDs and graphene accelerated the corrosion of metals, while few layered TMD nanosheets exhibited no promising effect. At the same time, we proposed different corrosion mechanisms according to the work function difference of nanomaterials as well as their oxygen reduction reaction activity to clarify the corrosion-promotion activity.