Hydrothermal synthesis of bismuth nanosheets for modified APTES-functionalized screen-printed carbon electrode in lead and cadmium detection

In this study, bismuth nanosheets (BiNS) were synthesized using the hydrothermal method and used to modify 3-aminopropyltriethoxysilane (APTES)-functionalized screen-printed electrodes (SPEs). The effect of hydrothermal reaction period (6, 7, and 8 h) on the properties of the synthesized BiNS was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM). XRD analysis revealed that pure bismuth was obtained for all samples. The BiNS synthesized for 6, 7, and 8 h have mean particle sizes of 79.9, 63.6, and 68.8 nm and thicknesses of 22.0, 23.3, and 30.8 nm, respectively. The synthesized BiNS were immobilized onto an APTES-functionalized SPE via self-assembly and then subjected to cyclic voltammetry and square wave anodic stripping voltammetry. The BiNS-modified APTES-functionalized SPE (BiNS/APTES-SPE) showed excellent performance in the detection of Pb(II) and Cd(II) with limits of detection of 2.3 and 4.1 ppb and sensitivities of 0.3897 and 0.1755 μA/ppb, respectively. The results showed that the BiNS-modified electrodes can be used in heavy metal sensors.