Freestanding anticorrosion hybrid materials based on coordination interaction between metal-quinoline compounds and TiO2-MgO film

Flower-like organic materials have been used for applications in supercapacitors, catalysis, corrosion science, but no report of flower from metal-organic compounds on porous inorganic surface has been available. Here, we report the successful fabrication of flowerlike organic-inorganic materials via the combination of TiO2-MgO film prepared on magnesium alloy through plasma electrolytic oxidation (PEO) as inorganic components and metal-quinoline, Na-8-hydroxyquinoline-5-sulfonic acid (NaHQS) and Co(II)-8-hydroxyquinoline-5-sulfonic acid (CoHQS), as the organic component. Interaction between the CoHQS complex and the porous inorganic materials then leads to the formation of flowerlike organic-inorganic coating on the magnesium surface. Furthermore, a detailed analysis of surface morphologies indicates that MHQS molecules are linked together via kinds of intermolecular hydrogen bonds and non-covalent pi-pi bonds between heterocyclic molecules. PEO-TiO2-CoHQS and PEO-TiO2-NaHQS exhibit enhanced electrochemical performance and chemical stability compared with the free MHQS, which was discussed based on polarization and impedance interpretation. This is attributed to the physical and chemical adsorption on the coating surface as well as the high surface area of the CoHQS in the nanoflowers. (C) 2020 Elsevier Inc. All rights reserved.