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

Abstract

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.