Bismuth nanoparticles decorated graphenated carbon nanotubes modified screen-printed electrode for mercury detection

A three-dimensional hierarchical network of bismuth nanoparticles decorated graphene-carbon nanotubes nanocomposite (Bi NPs@Gr-CNTs) was synthesized and employed for electrocatalytic detection of mercury (Hg (II)). The electrocatalyst was characterized via scanning electron microscopy, transmission electron microscopy, Energy-dispersive X-ray spectroscopy, X-ray diffraction, FT-IR, electrochemical impedance spectroscopy, and cyclic voltammetry. The electrocatalytic activity of Bi NPs@Gr-CNTs modified screen-printed carbon electrode (SPCE) toward Hg (II) was studied using cyclic voltammetry, and differential pulse voltammetry. The Bi NPs@Gr-CNTs/SPCE exhibited excellent electrocatalytic ability to Hg (II) in comparison to control electrodes. Under optimized conditions, Bi NPs@Gr-CNTs/SPCE exhibits excellent Hg (II) sensing attributes in the range of 1.0 nM–217.4 µM with 0.2 nM of detection limit. The electrode was specific for Hg (II) in presence of other metal ions ascribe excellent selectivity. Practicality of the method was demonstrated in tap water, fish oil tablet, human serum, and urine samples (spiked method), which presented acceptable recoveries.