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

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