Synthesis and evaluation of Cd-Co3O4@SGCN nanocomposites for photocatalytic degradation of RY-18 and inactivation of pathogenic bacteria.

In this research, cobalt oxide (Co3O4) nanoparticles and a series (1.3-9.3 mol%) of cadmium doped cobalt oxide (Cd-Co3O4) were synthesized using a simple co-precipitation method. All the prepared nanoparticles were characterized by FTIR, XRD, SEM, EDX and UV-Visible spectroscopy. The crystalline structure of Co3O4 was verified by XRD analysis, and the material's structural and electrical characteristics were successfully altered by Cd inclusion. The degradation efficiency of RY-18 decreased gradually with the increase of Cd concentration, and reached the maximum efficiency of 68% for 5.3% Cd-Co3O4, after 150 min of sunlight irradiation, compared to 33% for pure Co3O4. The photocatalytic efficiency was then reduced when the concentration of Cd was raised further (7.3% and 9.3%) because of the excessive electron-hole recombination induced by the existence of Cd. To further improve the photocatalytic activity, 5.3% Cd-Co3O4 was coupled with optimized 10%-70% SGCN and the 5.3% Cd-Co3O4@50% SGCN nanocomposite showed highest degradation performance because of improved light absorption and efficient charge transfer between the two components. Additionally, synthesized nanoparticles and nanocomposites exhibited antibacterial properties, which could be applied as antibacterial multifunctional materials in environmental remediation applications.