Sensing of heavy metal Pb 2+ ions in water utilizing the photonic structure of highly controlled hexagonal TiON/TiO 2 nanotubes.

The detection of heavy metals in water, especially Pb 2+ ions, is important due to their severe hazardous effects. To address this issue, a highly controlled hexagonal TiON/TiO 2 heterostructure has been synthesized in this study. The fabrication process involved the utilization of atomic layer deposition and direct current sputtering techniques to deposit TiO 2 and TiON layers onto a porous Al 2 O 3 membrane used as a template. The resulting heterostructure exhibits a well-ordered hollow tube structure with a diameter of 345 nm and a length of 1.2 µm. The electrochemical sensing of Pb 2+ ions in water is carried out using a cyclic voltammetry technique under both light and dark conditions. The concentration range for the Pb 2+ ions ranges from 10 -5 to 10 -1 M. The sensitivity values obtained for the sensor are 1.0 × 10 -6 in dark conditions and 1.0 × 10 -4 in light conditions. The remarkable enhancement in sensitivity under light illumination can be attributed to the increased activity and electron transfer facilitated by the presence of light. The sensor demonstrates excellent reproducibility, highlighting its reliability and consistency. These findings suggest that the proposed sensor holds great promise for the detection of Pb 2+ ions in water, thereby facilitating environmental monitoring, water quality assessment, and safety regulation across various industries. Furthermore, the eco-friendly and straightforward preparation techniques employed in its fabrication provide a significant advantage for practical and scalable implementation.