# Highly Dense TiO2 Nanorods as Potential Electrode Material for Electrochemical Detection of Multiple Heavy Metal Ions in Aqueous Medium

## TL;DR

This paper presents a new method to create dense TiO2 nanorods for detecting heavy metal ions in water, showing high sensitivity and stability.

## Contribution

The study introduces a hydrothermal method to grow highly dense TiO2 nanorods on ITO for simultaneous detection of multiple heavy metal ions.

## Key findings

- TiO2 nanorods showed high sensitivity for Cu2+ detection (~92.2 µA.mM−1.cm−2).
- The sensor had low detection limits for Cr3+, Cu2+, and Hg2+.
- The TiO2 NR-based sensor demonstrated stability over 30 days.

## Abstract

This study describes the direct deposition of extremely dense TiO2 nanorods (NRs) on an ITO substrate for the improved detection of heavy metal ions (HMIs). A facile hydrothermal method was employed to synthesize TiO2 NRs on the ITO substrate at ~130 °C. Synthesized TiO2 NRs were analyzed for morphological, structural, and electrochemical properties. As an electrode material, TiO2 NRs were used for the simultaneous detection of three HMIs (i.e., Cr3+, Cu2+, and Hg2+), which showed a remarkably high sensitivity of ~92.2 µA.mM−1.cm−2 for the Cu2+ ion. Relatively low sensitivities of ~15.6 µA.mM−1.cm−2 and ~19.67 µA.mM−1.cm−2 were recorded for the Cr3+ and Hg2+ ions, respectively. The fabricated TiO2 NR-based HMI sensor showed an effective dynamic linear detection range with low LOD values of ~21.7 mM, 37 mM, and ~ 28.5 mM for Cr3+, Cu2+, and Hg2+, respectively. The TiO2 NR-based HMI sensor exhibited efficient charge transfer over the electrode toward the trace detection of Cr3+, Cu2+, and Hg2+. Moreover, the reliability of the TiO2 NR-based HMI sensor was assessed, which exhibited a promising stability of 30 days. The obtained results indicate that TiO2 NRs grown on an ITO substrate are a promising electrode material for detecting hazardous Cr3+, Cu2+, and Hg2+ and might eventually be commercialized in the near future.