TiO₂-graphene hybrid nanostructures by atomic layer deposition with enhanced electrochemical performance for Pb(II) and Cd(II) detection

In this work, atomic layer deposition is applied to coat graphene nanosheets with TiO₂. The produced TiO₂-graphene (TiO₂-Gr) composites are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. It is revealed that TiO₂ is effectively deposited on the surface of graphene. The coatings have a highly controlled thickness. The electrochemical properties of the obtained TiO₂-Gr composites are investigated for detection of lead (Pb²⁺) and cadmium (Cd²⁺) ions by differential pulse anodic stripping voltammetry (DPASV). It is found that the TiO₂-Gr composite exhibits improved sensitivity for detection of these metal ions. The linear dynamic ranges are from 1.0 × 10^-8 M to 3.2 × 10^-5 M for Pb²⁺ and 6.0 × 10^-7 M to 3.2 × 10^-5 M for Cd²⁺, respectively. The detection limits (S/N = 3) are estimated to be 1.0 × 10^-10 M for Pb²⁺ and 2.0 × 10^-9 M for Cd²⁺, respectively.