▎ 摘　　要

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 x 10 (8) M to 3.2 x 10 (5) M for Pb2+ and 6.0 x 10 (7) M to 3.2 x 10 (5) M for Cd2+, respectively. The detection limits (S/N = 3) are estimated to be 1.0 x 10(-10) M for Pb2+ and 2.0 x 10(-9) M for Cd2+, respectively.