Preparation and inhibition properties of molybdate intercalated ZnAlCe layered double hydroxide

ZnAlCe layered double hydroxide intercalated by molybdate (ZnAlCe−MoO₄ LDH) was successfully synthesized by using co-precipitation method, and the morphology, structure of ZnAlCe−MoO₄ LDH were observed and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. The inhibition behavior of ZnAlCe−MoO₄ LDH for Q235 steel in 3.5%NaCl solution was determined by polarization curves, electrochemical impedance spectroscopy (EIS), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray photoelectron spectrometer (XPS) methods. The results shows that the synthesized ZnAlCe−MoO₄ LDH has a lamellar structure with a particle size of 0.1–2.0 μm, an average thickness of 30 nm, and a basal plane spacing of 0.898 nm. Compared with the addition of ZnAl layered double hydroxide intercalated by nitrate (ZnAl−NO₃ LDH) and ZnAl layered double hydroxide intercalated by molybdate (ZnAl−MoO₄ LDH) in 3.5% NaCl solution, Q235 steel in 3.5%NaCl + ZnAlCe−MoO₄ LDH solution has a lower corrosion current density, larger polarization resistance and a higher inhibition efficiency. The addition of ZnAlCe−MoO₄ LDH will reduce the chloride concentration in 3.5% NaCl solution by the anion exchanged with molybdate, and improve the corrosion resistance of Q235 steel owing to the formation of passive film with the composition of ferrous or iron molybdate and deposition film with zinc and cerium hydroxides. - Highlights: • ZnAlCe−MoO₄ LDH compound was successfully synthesized by co-precipitation method. • ZnAlCe−MoO₄ LDH has a better inhibition effect to Q235 steel in 3.5%NaCl solution. • The Cl⁻ ions in solution was partially exchanged with MoO₄²⁻ ions in host layers. • The passive film and deposition film were formed by the release of LDH compound.