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• Using PVP for size and stability modulation for the formation of ZIF-67. • Development of a hybrid coating by utilizing MAO, LDH, and PVP-mediated ZIF-67. • The coating showed incredible multifunctional properties, with excellent stability. • Superior corrosion resistance was achieved (R p = 6.47 × 108). • Remarkable photocatalytic degradation of rhodamine b dye was also observed. 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 × 108). 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. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel electron-transfer MOF material was synthesized and deposited onto the porous coating of AZ31Mg alloy. This material was modified by transition metallic oxides. • The electronic structures of SnOF, ZnOF, and VOF complexes varied, impacting the morphologies of the samples and influencing their electrochemical and photocatalytic activities. • SnOF aggregation on the PEO layer sealed structural defects, creating a barrier against corrosive ion infiltration and resulting in high electrochemical stability. • SnOF and VOF samples showed high efficiency in crystal violet degradation after exposure to visible light. VOF demonstrated remarkable efficiency and stability, surpassing the performance of previously reported catalysts. • The degradation mechanism and the interaction between crystal violet and the catalyst were thoroughly examined, along with the reactive species responsible for degradation. In the pursuit of multifunctional coatings, the controlled growth of materials on stationary platforms holds paramount importance for achieving superior corrosion protection and optimal photocatalytic performance. This study introduces a cutting-edge approach, intertwining bifunctional metal-organic frameworks (MOFs) seamlessly into defective MgO layers produced by the anodic oxidation of AZ31 alloy. Key metallic oxides of Zn, Sn, and V take center stage as metallic sources for MOF formation, complemented by the organic prowess of l -Tryptophan as an α-amino acid linker. Leveraging the electronic structure of metallic oxides reacting with tryptophan molecules, controlled morphologies with distinct characteristics are induced on the defective surface of the MgO layer, enabling the precise modulation of surface defects. The hybrid composite demonstrates an adaptive microstructure in diverse aqueous environments, offering dual functionality with electrochemical stability and visible light photocatalytic activity for crystal violet degradation. Among the samples, the SnOF complex exhibited remarkable electrochemical stability with a low corrosion current density of 7.50 × 10−10 A·cm−2, along with a 94.56 % degradation efficiency after 90 min under visible light exposure. The VOF complex, under similar visible light conditions, demonstrated exceptional performance with a higher degradation efficiency of 97.79 % and excellent electrochemical stability characterized by a corrosion current density of 3.26 × 10−9 A·cm−2. Additionally, Density Functional Theory (DFT) computations shed light on the basic bonding patterns between MOFs and inorganic components, providing electronic understanding of their electrochemical and photocatalytic activities. [Display omitted] [ABSTRACT FROM AUTHOR]

• LDH flakes provided efficient sealing of the porous layer, thereby improving durability. • SnO 2 and WO 3 were incorporated simultaneously in LDH flakes under hydrothermal conditions. • LDH-SnO 2 -WO 3 exhibited exceptional electrochemical and photocatalytic performance. • Computational analyses elucidated the detailed interactions between metal oxides and LDH surfaces. This study explores the potential of LDH flakes decorated with metallic oxide nanoparticles to function as both anti-corrosion barriers against chloride anions and heterogeneous photocatalysts for tetracycline degradation under visible light. The process involves modifying the primarily MgO-based inorganic porous film by growing a MgFe LDH film, followed by the individual and dual incorporation of SnO 2 and WO 3 nanoparticles. The dual incorporation of these nanoparticles into the LDH matrix leads to synergistic interactions, effectively sealing pre-existing defects within LDH flakes and facilitating the in-situ formation of catalytic sites through oxidation and the induction of surface oxygen vacancy defects, which synergistically contribute to the enhancement of both electrochemical and photocatalytic activities. The enhanced electrochemical stability is reflected in a significant reduction in corrosion current density by 4 orders of magnitude compared to unmodified porous film. Additionally, the decorated film demonstrates sustained photocatalytic functionality, achieving significant degradation (95.5%) of tetracycline within two hours. This study presents a novel approach, highlighting the dual effectiveness of LDHs decorated by dual metal oxides as an anti-corrosive agent and photocatalyst, with promising implications for environmental remediation and wastewater purification. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel approach to high-performance hybrid materials for corrosion prevention. • WO 3 /PPVA hybrids deposited in a fragmented manner, forming a "laminar reef-like structure. • PPVA-sealed WO 3 -based coating showed superior corrosion resistance compared to other samples. • Computational analyses to elucidate the hybrid formation mechanism. Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties. However, the integration of polymeric frameworks with MgO/WO 3 composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties. In this study, we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis (PE) of AZ31 Mg alloy by incorporating WO 3 with partially phosphorated poly(vinyl alcohol) (PPVA). Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte, one with and one without WO 3 nanoparticles, which were subsequently immersed in an aqueous solution of PPVA. Incorporating PPVA into the WO 3 -MgO layer resulted in hybrids being deposited in a fragmented manner, creating a '' laminar reef-like structure '' that sealed most of the structural defects in the layer. The PPVA-sealed WO 3 -based coating exhibited superior corrosion resistance compared to the other samples. Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO 3 hybrids on the MgO layer. These findings suggest that PPVA-WO 3 -MgO hybrid coatings can potentially improve corrosion resistance in various fields. [ABSTRACT FROM AUTHOR]

• An innovative two-step hydrothermal method was developed to form MOF on LDH surface. • Co-Trp self-assembled network formed via electrophilic and nucleophilic interactions. • A cloud-like structure of MOF-LDH was successfully obtained. • MOF-LDH hybrids provided superior corrosion protection. The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide usability. In this work, a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide (LDH) films using novel metal-organic frameworks (MOFs). Initially, Mg-Al LDH nanocontainers, grown on a magnesium oxide layer produced through plasma electrolytic oxidation (PEO) of AZ31 Mg alloy substrate, were intercalated with cobalt via an oxidation route, providing the metallic coordination center for the MOF formation. In the subsequent step, a pioneering technique is introduced, utilizing tryptophan as the organic linker for the first time at a pH of 10. The self-assembly of cobalt- tryptophan complex, driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites, facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's film. The resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.% NaCl solution, surpassing the performance of PEO and pure LDH coatings. This enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF, effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic substrate. The formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations. [ABSTRACT FROM AUTHOR]