L-Cysteine functionalized coral-like Ag doped MnO2 nanostructures for the real-time electrochemical detection of lead and cadmium ions

Abstract

In this report, L-Cysteine functionalized Ag@MnO2 nanocomposite was prepared for selective, rapid, and instantaneous electrochemical sensing of heavy metal ions (HMIs). Hydrothermal method was employed to synthesize L-Cysteine functionalized Ag@MnO2 nanocomposites. The composition and morphology of L-Cys/Ag@MnO2 were characterized by advanced techniques such as XRD, FTIR, UV-Vis and FESEM analysis. XRD spectra confirmed the synthesis of tetragonal L-Cys/Ag@MnO2, while FESEM confirmed the formation of coral like nanostructures. Coral like L-Cys/Ag@MnO2 with sufficient open pores provided high surface area and large number of active sites for sensing of HMIs. The electrochemical parameters were optimized i.e., pH effect, deposition potential, deposition time, and impact of interfering species to enhance HMIs detection. Under optimized conditions, the designed sensor exhibited high sensitivity towards the solution of both Cd+2 and Pb+2 ions over a wide range from 0.1 μM to 0.005 μM of Cd+2 and Pb+2, respectively with LOD = 0.052 nM for Pb+2 and 0.065 nM for Cd+2. The developed sensor's practical applicability was also tested in tap water. Due to the high conductivity, synergistic effect, and high electron transfer kinetics of the prepared material, as designed sensor can be utilized for sensing other toxic metal ions in real samples.