An Electrochemical Sensor based on p-aminothiophenol/Au Nanoparticle-Decorated HxTiS2 Nanosheets for Specific Detection of Picomolar Cu (II)

An ultrasensitive electrochemical sensor for Cu 2+ detection was first developed based on p-aminothiophenol (PATP) anchored on the surface of Au nanoparticle-decorated hydrogen-incorporated TiS 2 nanosheets (PATP/Au-H x TiS 2 ). In the synthesis process, the plane edges of H x TiS 2 nanosheets offered Au nanoparticles with incubation sites for the heterogeneous nucleation and growth. On the other hand, Au nanoparticles were not only served as an excellent electrical catalyst to facilitate electron transfer and as a substrate for loading PATP molecules by Au-S valent bonds, but also could effectively avoid the aggregation of H x TiS 2 nanosheets . Due to the synergetic effects from Au-H x TiS 2 for signal amplification, the as-formed electrochemical sensor exhibited highly sensitive and selective assaying of Cu 2+ with a detection limit of 90 pM (3σ) and a linear range from 0.2   nM to 5   μM, under optimal conditions. Its specificity was ascribed to the strong coordination interaction between Cu 2+ and N atoms of imine moieties in PATP after electrochemical oxidation .