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

An ultrasensitive electrochemical sensor for Cu2+ detection was first developed based on p-aminothiophenol (PATP) anchored on the surface of Au nanoparticle-decorated hydrogen-incorporated TiS2 nanosheets (PATP/Au-HxTiS2). In the synthesis process, the plane edges of HxTiS2 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 HxTiS2 nanosheets. Due to the synergetic effects from Au-HxTiS2 for signal amplification, the as-formed electrochemical sensor exhibited highly sensitive and selective assaying of Cu2+ 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 Cu2+ and N atoms of imine moieties in PATP after electrochemical oxidation.