Cu/CuO/ZnO/PPy heterojunction material was prepared for Hg2+ anti-interference detection in seawater

Abstract

Hg2+ pollution poses a major threat to human health and the ecological environment, but there is still a lack of direct and sensitive Hg2+ detection technology. In this study, Cu/CuO/ZnO wires were prepared by alkaline oxidation and hydrothermal methods. Polypyrrole (PPy) was covered on the surface of the material by electrochemical polymerization. Using the principle of electrochemical signal response driven by p-n junction barrier, the material was used for the direct electrochemical detection of Hg2+ and was tested by differential pulse voltammetry. The composite has a good linear relationship in the Hg2+ concentration range of 200–1600 nmol/L, and has ultra-high sensitivity (1,010.82 μA∙L/(nmol∙cm2)) and ultra-low detection limit (2.1 pmol/L). The new sensing mode based on the interface barrier eliminates the interference of other ions. The recovery rate of Hg2+ in tap water, river water and sea water is 97.3%–105.0%, and the RSD is 1.8%–5.6%. This method using p-n junction barrier can be extended to the development and research of other sensors for detecting heavy metal ions.