Green Synthesis of CdS and CdS/rGO Nanocomposites: Evaluation of Electrochemical, Antimicrobial, and Photocatalytic Properties

The green approach has been employed for the synthesis of various types of nanomaterials including metal nanoparticles, metal oxides, and carbon-based nanomaterials. These processes involve natural sources that contain bioactive compounds that act as reducing, stabilizing, and capping agents for the formation and stabilization of nanomaterials. This study reports the green synthesis of CdS and CdS/rGO nanocomposites using Lactobacillus bacteria. The UV-visible spectrophotometer, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy spectra confirm the synthesis of the nanocomposite. The electrochemical characterization using cyclic voltammetry, differential pulse voltammetry, and EIS revealed that the CdS/rGO nanocomposites showed a higher electron transfer rate compared with CdS nanoparticles, indicating the potential of the nanocomposites for biosensing applications. The zone of inhibition revealed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus for both CdS nanoparticles and CdS/rGO nanocomposites. Additionally, CdS/rGO nanoparticles exhibited high photocatalytic activity for the degradation of methylene blue dye. Overall, this study demonstrates that the synthesized CdS and CdS/rGO nanocomposites have good electrochemical properties, photocatalytic, and antimicrobial activity and, therefore, can be employed for various applications such as biosensing, photocatalysis, and antimicrobial activity.