Colorimetric detection of Hg2+ based on the enhanced oxidase-mimic activity of CuO/Au@Cu3(BTC)2 triggered by Hg2+

Abstract

It is imperative to develop a rapid detection method for Hg²⁺ due to its harm to human health and the ecological environment. In this research, CuO/Au@Cu₃(BTC)₂ was synthesized through reducing HAuCl₄ by Cu_xO@Cu₃(BTC)₂, which was obtained by reducing Cu₃(BTC)₂ with hydrazine hydrate. The oxidase-mimic activity of CuO/Au@Cu₃(BTC)₂ can be enhanced by Hg²⁺ through forming a Au–Hg alloy. Therefore, a colorimetric method was designed for Hg²⁺ detection with a linear relationship in the 0.05–25 μM range and a limit of detection of 9.7 nM. This strategy exhibited a strong selectivity to Hg²⁺ and was applied in a real water sample with reliable recoveries. This work provides a possibility for the rapid detection of Hg²⁺.