Tailoring electrochemical and photocatalytic properties of NiAl layered double hydroxide coatings on porous MgO layer through zinc oxide decoration

The decoration of NiAl layered double hydroxide (NiAl LDH) coatings on porous MgO composites with ZnO nanoparticles offers a novel approach to improving both corrosion resistance and photocatalytic activity. In this study, a porous MgO layer was fabricated via plasma electrolytic oxidation (PEO) of AZ31 alloy, serving as a substrate for hydrothermally synthesized NiAl LDH coatings. ZnO nanoparticles were subsequently incorporated using two methods namely hydrothermal and ultrasonic deposition. Among these, ultrasonic deposition was found to be more effective in filling surface imperfections, enhancing the barrier effect, and increasing active sites for photocatalytic reactions. The ZnO-decorated LDH coating prepared via ultrasonic deposition exhibited superior electrochemical performance, achieving an I corr of 8.09 × 10 −11 A/cm 2 and the highest impedance values in EIS analysis. Additionally, this coating achieved 99 % degradation of rhodamine B dye under visible light within 40 min, highlighting its potential for corrosion protection and environmental remediation.