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This study investigates the enhancement of surface properties in TiO2-based coatings on the Ti-6Al-4V alloy through micro-arc oxidation (MAO), employing stevia sugar as a novel additive. By incorporating stevia sugar into acetate–glycerophosphate–tetraethoxysilane solutions used in MAO treatment, the porous morphology of TiO2-based oxide layers is regulated. The incorporation of stevia moderates plasma discharge intensity, facilitating the formation of a uniform silicon-rich structure characterized by reduced porosity and pore size. This effect is attributed to the interaction between stevia and tetraethyl orthosilicate (TEOS), which modifies the TEOS hydrolysis process, thereby enhancing structural uniformity and stability while concurrently reducing plasma discharge intensity. Additionally, theoretical calculations offer a valuable understanding of the reactivity and interactions of stevia, TEOS, and their complex during the MAO process, laying the groundwork for further research and optimization in this promising field. [ABSTRACT FROM AUTHOR]

The convergence of organic compounds and their incorporation into inorganic layers paves the way for pioneering organic–inorganic hybrid materials with finely tuned, precise functional properties, promising a new era of advanced applications that push the boundaries of current technology. This study employs a pH-responsive chelation approach to control defects in MgAl-LDH, aiming to enhance its electrochemical and photocatalytic properties. This involves the synthesis of MgAl-LDH on plasma-assisted oxidized substrates, followed by the sequential introduction of [EDTA]4− and [Zn(EDTA)]2− anions into the LDH galleries via an anion exchange route. The chelation of EDTA with the metallic ions is pH-dependent, where a higher pH value encourages the inclusion of [EDTA]4− anions, supported by the stability of LDH flakes, while a lower pH value facilitates the introduction of [Zn(EDTA)]2− anions. The results show that the integration of [Zn(EDTA)]2− anions leads to a more compact structure and a reduction in the size of LDH flakes, effectively sealing existing defects within the hybrid material. When exposed to a 3.5% NaCl solution, the LDH–EDTA–Zn sample exhibited superior electrochemical stability, characterized by a lower corrosion current density (2.12 × 10−9 A cm−2) and higher total polarization resistance (2.73 × 107 Ω cm2). Moreover, the LDH–EDTA–Zn sample demonstrated exceptional photocatalytic efficiency, effectively decomposing rhodamine dye in an aqueous solution, attaining an impressive photocatalytic efficiency of 99.7% within just 25 minutes, while maintaining stability throughout five consecutive cycles, surpassing the performance of previously reported LDH-based catalysts. The interaction mechanism between the chelated anions and the LDH surface was elucidated by applying density functional theory. This research presents a promising approach for developing advanced organic–inorganic hybrid materials with exceptional electrochemical and photocatalytic performance. [ABSTRACT FROM AUTHOR]