Robust Synthesis of GO-PtNPs Nanocomposites: A Highly Selective Colorimetric Sensor for Mercury Ion (II) Detection

Due to their high toxicity and ongoing bioaccumulation, mercury ions (Hg²⁺) can cause significant harm to both the environment and human health. Therefore, rapid, accurate, and selective methods for Hg²⁺ detection are highly desirable. Herein, we present a simple method for depositing platinum nanoparticles (PtNPs) on graphene oxide (GO) to obtain graphene oxide-PtNPs (GO-PtNPs). The fabricated GO-PtNPs exhibit excellent peroxidase-like activity and high stability. Further, the GO-PtNPs nanozymes preferentially reduced Hg²⁺, thereby inhibiting the catalytic activity. By monitoring the color change in the chromogenic substrate, Hg²⁺ can be detected within 15 min. With a detection limit of 88.3 pM, the GO-PtNPs system may be employed to detect Hg²⁺ in a linear range of 0.1 nM to 10 μM. The simplicity and low cost of the proposed approach as well as its applicability to complicated samples demonstrate its capacity for mercury sensing in environmental samples.