Corrosion inhibition of steel using mesoporous silica nanocontainers incorporated in the polypyrrole

•Mesoporous silica (MSInh) acts as the host of molybdate (corrosion inhibitor).•pH-sensitive release of corrosion inhibitor in the corrosive media is observed.•MoO42− releases from the MSInh in the pH=8 due the releasing of OH− in the surface.•MoO42− releases from MSInh in response of corrosive ion presence in solution. Mesoporous silica nanocontainer powders were applied as corrosion inhibitor hosts. These powders were dispersed in the polypyrrole matrix by electropolymerization technique. The protection properties of these composite coatings with and without inhibitor were studied in 2gdm−3 chloride ion solutions at constant pH. Open circuit potential (OCP), inductive coupled plasma (ICP), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and Fourier transform infrared spectroscopy (FTIR) results showed that the substrates were protected due to the release of corrosion inhibitor from mesoporous silica in the chloride media compared to the coatings without corrosion inhibitor. The released corrosion inhibitor reacted with substrate and made a protective phase during corrosion. This phase can heal the corroded area as a self-healing compound.