Development of photocatalytically active coating on cp-Ti by anodization

Abstract

Abstract TiO2 has emerged as an excellent photocatalyst over the last few decades. TiO2 based photocatalysts find application in pollutant control, dye degradation, self-sterilizing coatings, self-cleaning materials, and so on. The present work focuses on the development of TiO2 coatings on a commercially pure titanium substrate (cp-Ti) with a nanotubular morphology by the process of anodization and aims to characterize the coatings formed and to study the effect of anodization process parameters (voltage, time and electrolyte concentration) on the morphology of the coatings. The anodization circuit consists of the cp-Ti sample as the anode, a platinum cathode, and an organic electrolyte with fluoride ions. The base electrolyte used in this work was a 9:1 by volume mixture of ethylene glycol and H2O. Experiments were conducted at combinations of 25\u202fV, 30\u202fV, and 40\u202fV at 1\u202fh and 1.5\u202fh. The coated samples were heat-treated at 500\u202f°C for 1\u202fh in ambient conditions. The thickness of the coatings was measured, after which FESEM was performed to study the morphology of the coatings formed. The phases present in the coating were studied using XRD. The bandgap of the samples was measured using UV–Vis diffuse reflectance spectrometry. The FESEM images clearly showed the formation of a nanotubular coating. The diameters of the tubes increased with an increase in the voltage while the XRD results confirmed the presence of the anatase TiO2 phase.