Development of Antibacterial V/TiO<sub>2</sub>-Based Galvanic Coatings for Combating Biocorrosion
Mohandas Jaya Deepa, S.R. Arunima, Liju Elias, S.M.A. Shibli
Abstract
Recently, TiO2 crystals have been modified by transition-metal dopants with different physicochemical structures to attain distinguished properties. Considering the similar ionic sizes of V4+ (0.058 nm) and Ti4+ (0.061 nm), vanadium in the +4 state can be effectively incorporated into the crystal lattice of TiO2 to tune the band gap energy by creating an impurity energy level (V5+/V4+) below the conduction band (2.1 eV) and retaining the anatase phase. In vanadium-incorporated TiO2 (V/TiO2), V4+ is a good dopant candidate as it can increase the lifetime of the charge carrier and reduce the electron–hole recombination rate, which results in high antibacterial activity under visible light irradiation. The present study explores the V/TiO2-based hot-dip zinc coating with enhanced electrochemical properties and long-term stability for combating biocorrosion. All the composites and the coatings are characterized by different techniques, including X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray analysis, confocal laser scanning microscopy, optical surface profilometry, and X-ray photoelectron spectroscopy. The biofilm formation assay and the cell viability assay reveal that the tuned composition of the V/TiO2-based hot-dip zinc coating effectively kills the adherent bacteria and inhibits biofilm formation on the surface. The high-charge-transfer resistance (225.67, 223.63, and 242.35 Ω cm2) and the high-inhibition efficiency (92.24, 92.30, and 92.02%) of the tuned composition of the V/TiO2-based hot-dip zinc coating confirm its efficient and sustainable antibiocorrosion performance and long-term stability even after an exposure period of 21 days in different bacterial environments. With the inherent antibacterial properties and antibiocorrosion performance of the developed V/TiO2-based hot-dip zinc coating, the mild steel substrates can find potential application in different fields, including aquatic and marine environments.