Simple laser-induced graphene fiber electrode fabrication for high-performance heavy-metal sensing

[Display omitted] •Laser induced graphene fiber (LIGF) electrode was fabricated and it was applied for realizing a high-performance heavy-metal sensor for first time.•LIGF electrode was fabricated by a simple laser irradiation on polyimide film.•LIGF layer is porous to increase the active surface area and electrically conductive.•LIGF with electroplated bismuth nanoparticles showed excellent Cd and Pb ions detection capability using stripping voltammetry. In this paper, we describe the simple fabrication and characterization of a high-performing heavy metal sensor by using laser-induced graphene fiber (LIGF) electrodes for simultaneous detection of cadmium (Cd2+) and lead (Pb2+) ions. Both LIG and LIGF were grown via extremely simple and fast method, compared to conventional graphene synthesis, on a commercial polyimide film by irradiating CO2 infrared laser with the appropriate energy level (46 J/cm2 in this work). Fabricated LIG and LIGF were analyzed by FE-SEM and Raman spectroscopy, which showed that the LIGF structure was composed of randomly stacked three-dimensional porous graphene layers and fibers. On the surface of the LIGF working electrode, bismuth was electro-deposited in-situ for the electrochemical detection of heavy metal ions. The fabricated LIGF electrode heavy metal sensor was used for the simultaneous detection of Cd and Pb ions in 0.1 M acetate buffer solution at pH 4.5 by square wave anodic stripping voltammetry. The fabricated LIGF-based heavy-metal sensor showed high sensitivity (0.19 and 0.20 μA μg−1 L for Cd and Pb ions), broad linear detection ranges (1.0 to 140.0 μg/L for Cd and Pb ions), and low detection limits (0.4 μg/L (S/N = 3) for both Cd and Pb ions), showing great promise in high-performance heavy metal detection applications that require fast and simple manufacturing practices.