Fabrication of an Innovative Lead-Ions Sensitive Electrode Based on Thio-semicarbazide Derivative Modified Nanoporous Silicon

Background: The detection of heavy metals in the environment is of great importance due to their high toxicity. Methods: A multi-step graft route was designed for anchoring thiosemicarbazide derivative (TSCD) groups onto the porous silicon (PS) surface. The reaction efficiency at each step functionalization was confirmed using FT-IR spectra, and the XPS analysis results confirmed the modification of thiosemicarbazide derivative. The morphology change of the modified PS was studied by AFM characterization. Results: The results display that the currents of Pb0 oxidation increase with the accumulated Pb2+ concentration and the TSCD-PS has a strongest sensitive to Pb2+ at pH = 4.0. The results display that the anodic peak current densities increase with the increasing Pb2+ concentration and they have a good fitting with a second order exponential function of I = -156exp(-1562[Pb2+]) - 260exp(-105 [Pb2+]) + 446 (R2 = 0.99). Conclusion: The TSCD-PS shows the property to determinate Pb2+ in aqueous solution, which demonstrates that the modified PS is expected to be a promising platform for detecting toxic metal ions.