Influence of gold nanostructures incorporated into sodium montmorillonite clay based on LbL films for detection of metal traces ions

We report the effects of different gold nanostructures incorporated into sodium montmorillonite clay mineral (Na+-MMT) through thin films based on electrostatic interactions. The nanocomposite films were fabricated by layer-by-layer (LbL) technique using gold nanosphere (AuNSs) and gold nanorods (AuNRs) as cationic colloidal solutions, interacting with Na+-MMT clay as anionic dispersion. Higher performance was evaluated from electrochemical measurements for the detection of metal ions traces (Cd2+ and Cu2+). The interactions between materials were confirmed by UV-vis and FTIR spectroscopies and the effects of the Au nanostructures shape on Na+-MMT clay structures properties are confirmed by X-ray diffraction patterns. The results demonstrate that the AuNRs increase the lamellar space of Na+-MMT clay, consequently, increasing the roughness and favoring directly electrochemical response, with higher sensitivity and lower limits detection. Recovery was found to be 98.1% for cadmium but as high as 103.1% for copper, indicating that the modified electrode provides excellent reproducibility, stability, and promising applicability in the real water sample.