Facile synthesis of novel hierarchical core@shell structural magnetic nanovehicle Fe3O4@ZnAlCe-MoO4-LDHs for carbon steel protection.

• The Fe 3 O 4 @ZnAlCe-MoO 4 -LDHs composite was synthesized by co-precipitation method. • The composite possesses soluble Cl−/magnetic field responsive properties. • The composite has high corrosion inhibition efficiency for Q235 steel. • The nanovehicle Fe 3 O 4 @ZnAlCe-MoO 4 -LDHs can be regenerated and recycled. A novel dual-stimuli-responsive inhibitor nanovehicle Fe 3 O 4 @ZnAlCe-MoO 4 -LDHs was synthesized via a facile double-drop co-precipitation method. The obtained Fe 3 O 4 @ZnAlCe-MoO 4 -LDHs presents well-defined hierarchical core–shell structure with MoO 4 2− corrosion inhibitor intercalated lamellar ZnAlCe-LDHs nanocrystals of ~30 nm assembling closely to Fe 3 O 4 microspheres surface, possessing moderate inhibitor loading of 9.72% and strong superparamagnetism. The release results reveal that in the same NaCl solution, the rel eq (equilibrium release amount, 49.1%) and t 0.5 (the time for release fraction of 50%, 4.5 h) were delayed much by magnetic field relative to non-magnetic field case (51.6%, 2.5 h). And the rel eq decreased with magnetic field strength, accompanied by the prolongation of t 0.5 , up to 6 h under a 1350 Gs magnet. Similarly, with keeping the magnetic field unvaried, the decline of NaCl solution concentration led to lower rel eq and longer t 0.5. The kinetic fittings displayed that for all cases, the release process is inclusive of interlayer diffusion between LDHs layers (path I), interparticle diffusion among stacked LDHs crystals (path II) and diffusion between magnetic nanoparticles (path III). Compared to non-magnetic field, diffusion difficulties of path III was greatly enhanced under magnetic field. While for low-Cl− concentration system, the path I were limited effectively. Thus these two stimulus response factors can be used to regulate release behavior. Meanwhile, the protection efficiency of the nanovehicle for Q235 steel is higher than 88% because of the formation of inhibition film (ferrous or iron molybdate and hydroxide of zinc and cerium) on Q235 surface and the reduction of Cl− concentration in the solution via ion exchange. Moreover, the nanovehicle, presenting outstanding structural and magnetic stabilities, can be regenerated by a series of experiments, owning appreciable recycling performance and good anticorrosion activity in six recycles. [ABSTRACT FROM AUTHOR]