Titanate nanotubes from titanium dioxide powder with polymorphic mixture for rhodamine B degradation

Abstract

In this work, titanate nanotubes (TiTNs) were obtained from titanium dioxide (TiO2–ABR) polymorphic phases (Anatase = A, Brookite = B, and Rutile = R) via alkaline hydrothermal method, aiming photocatalytic application. The synthesized materials were analyzed structurally and morphologically. According to X-Ray Diffractometry (XRD) pattern, the TiO2–ABR was composed of Anatase (41.16 ± 0.67%), Brookite (31.19 ± 0.58%), and Rutile (27.66 ± 0.43%). Furthermore, XRD results displayed the formation of TiTNs with a plane at 9.58° (200). TiTNs presented an average outer diameter of 14.2 nm, inner diameter, and interlamellar of 3.9 nm and 0.72 nm, respectively. Brunauer-Emmett-Teller (BET) analysis suggested a relevant increase in the surface area by approximately 60% compared to the TiO2–ABR precursor, TiTNs also showed an estimated band gap of 3.47 eV. Photocatalytic activity of TiTNs in the degradation of rhodamine B (RhB) dye under Ultraviolet-Visible (UV–Vis) light irradiation was evaluated, showing that 90% of the dye was degraded after 2 h of exposure, where the superoxide radicals are the main radicals in the oxidation of RhB molecules. Thus, the synthesized material presented shows promising properties and high stability for photocatalytic application.