Anodic electrodeposition of MIL-53(Al) thin films on aluminum: Synthesis, characterization, and potential for direct electric heating

Abstract

This study presents the first successful anodic electrodeposition (AED) of MIL-53(Al) thin films on aluminum electrodes, using a novel synthesis approach involving a DMF-water solvent mixture and potassium chloride as a supporting electrolyte. The aim was to optimize the synthesis parameters to control the crystallinity, morphology, and porosity of the films, and to evaluate their potential applications in direct electric heating. The crystallinity, morphology, and porosity of the obtained films were controlled by systematically varying process parameters such as current density, electrolyte concentration, and deposition time. The study also assessed the impact of different post-synthesis washing protocols on film purity and adherence. Characterization techniques including XRD, XPS, FTIR, SEM, TEM, EDX, BET, and TGA were employed to analyze the structural and compositional properties of the synthesized thin films. The study found that higher current densities and higher electrolyte concentrations favored better crystallinity, while lower current densities favored larger crystal growth. High-performing films achieved a BET surface area of 876.2 m² g^-1, indicating great potential for gas separation and adsorption applications. A methanol–water and DMF washing sequence was optimal for achieving film purity and adherence. The films exhibited thermal stability up to 500 °C. The potential for direct electric heating was demonstrated, with the electrode surface reaching 68.3 °C after 5 min at 3 A. This work establishes AED as a scalable and cost-effective method for producing customizable thin film MOFs, suitable for advanced applications such as gas storage, catalysis, and sensing. It expands the possibilities for the application of MOFs and suggests future research directions to explore other MOF systems and their practical performance in realistic conditions.