A disposable and flexible electrochemical sensor for the sensitive detection of heavy metals based on a one-step laser-induced surface modification: A new strategy for the batch fabrication of sensors

Abstract

In this study, we developed a disposable and flexible electrochemical sensor for the sensitive determination of heavy metal ions based on an efficient one-step laser-induced surface modification. A flexible polyimide film was used as the substrate of the sensor, which was sprayed with a corresponding bismuth precursor ink to form a sensitive coating, i.e., bismuth nanoparticle@laser-induced graphene (BiNP@LIG). Then, Nafion was pipetted on BiNP@LIG to form a cover layer. The BiNP@LIG nanocomposite was successfully synthesized by laser irradiation (470 nm), and the composition of the obtained material was further verified by X-ray diffraction, energy dispersive spectroscopy and Raman spectroscopy. Moreover, the morphology of the BiNP@LIG nanocomposite was investigated by scanning electron microscopy, which showed that BiNPs were uniformly distributed on LIG, and the average diameter of the BiNPs was approximately 38 nm. Finally, a possible sensing mechanism of the Nafion/BiNP@LIG electrochemical sensor was proposed. The results show that the proposed electrochemical sensor exhibited satisfactory sensitivity and stability for the detection of Pb(II) and Cd(II). In addition, the laser-induced surface modification method proposed in this study could be an attractive candidate for the batch fabrication of sensors based on the noncontact, computer-controlled and pattern-making characteristics of laser induction.