Effective multifunctional coatings with polyvinylpyrrolidone-enhanced ZIF-67 and zinc iron layered double hydroxide on microarc oxidation treated AZ31 magnesium alloy

Modulating metal-organic framework’s(MOF)crystallinity and size using a polymer,in conjunction with a high surface area of layered double hydroxide,yields an effective strategy for concurrently enhancing the electrochemical and photocatalytic performance.In this study,we present the development of an optimized nanocomposite,denoted as 0.5PVP/ZIF-67,developed on AZ31 magnesium alloy,serving as an efficient and durable multifunctional coating.This novel strategy aims to enhance the overall performance of the porous coating through the integration of microarc oxidation(MAO),ZnFe LDH backbone,and ZIF-67 formation facilitated by the addition of polyvinylpyrrolidone(PVP),resulting in a three-dimensional,highly efficient,and multifunctional material.The incorporation of 0.5 g of PVP proved to be effective in the size modulation of ZIF-67,which formed a corrosion-resistant top layer,improving the total polarization resistance(R_(p)=8.20×10^(8)).The dual functionality exhibited by this hybrid architecture positions it as a promising candidate for mitigating environmental pollution,degrading 97.93%of Rhodamine B dye in 45 min.Moreover,the sample displayed exceptional degradation efficiency(96.17%)after 5 cycles.This study illuminates the potential of nanocomposites as electrochemically stable and photocatalytically active materials,laying the foundation for the advancements of next-generation multifunctional frameworks.

Enhancing the photocatalytic performance and chemical durability of AZ31 magnesium alloy by incorporating two types of nanoparticles through plasma electrolytic oxidation

The difficulty in achieving a balance between photocatalytic efficiency and chemical robustness has been a barrier to the broad use of Mg O as a versatile material, mainly because of its restricted surface activity. To overcome this, a novel surface modification technique is proposed. It involves the integration of highly stable SnO2and WO3nanoparticles, which are known to enhance surface activity. This approach aims to achieve an optimal balance between efficiency and stability by finely tuning the structure-surface reactivity relationship.The technique utilizes a plasma electrolytic oxidation(PEO) method. In this method, both the AZ31 Mg alloy substrate and SnO2/WO3precursors undergo simultaneous oxidation. This is induced by high-energy plasma generated through high voltage. The results demonstrate that this process yields a Mg O layer with a homogeneous dispersion of SnO2and WO3nanoparticles, significantly enhancing its overall performance. Corrosion measurements demonstrated enhanced electrochemical stability against chloride ions. The dual incorporation resulted in a hybrid film exhibiting a corrosion current density value of 7.57 × 10-11A/cm2and a high outer layer resistance of 5.17 × 10~7Ω.cm2.Additionally, the dual incorporation of SnO2and WO3nanoparticles enhances the photocatalytic activity of AZ31 Mg towards tetracycline degradation. This results in a photocatalytic efficiency of 89.54% within 2 h of exposure to visible light using the BA-W-Sn sample, which outperforms other samples. This integrated strategy enables the study to contribute significantly to expanding the practical applications of Mg O-based materials. It does so by simultaneously enhancing their photocatalytic activity and chemical stability.