Synthesis, characterization and application of Co/Co3O4 nanocomposites as an effective photocatalyst for discoloration of organic dye contaminants in wastewater and antibacterial properties

• Expressed good antibacterial activity against clinical pathogens. • Synthesized Co/Co 3 O 4 nanocomposites had a size of around 12–71 nm. • Co/Co 3 O 4 nanocomposites have shown antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria. • NCs synthesized utilizing the SDBS degraded 69.5% of AB92 in 120 min of illumination. • Maximum inhibition zone sizes for nanocomposites against P. aeruginosa & . B. subtilis are 9 mm & 11 mm. Contamination of surface water with dye chemical compounds and/or biological substances, even in small amounts, can affect the health of humans and other organisms. The photocatalytic oxidation process has been considered as a commercial technique to remove environmental pollutants. In the current study, we reported the synthesis of Co/Co 3 O 4 nanocomposites investigated for their photocatalytic and antimicrobial activities. The affecting parameters (various surfactants and calcination) on the synthesis process were investigated. The synthesis of Co/Co 3 O 4 nanocomposites was confirmed via methodical characterization such as SEM, FT-IR, XRD, VSM, EDX, CV and DRS investigations. Well diffusion assay and bacterial cell viability assay were executed against clinical pathogens to prepare the antibacterial activity of synthesized Co/Co 3 O 4 nanocomposites. Also, the photocatalytic activity of nano-catalysts was concluded against the organic colors (acid blue 92 and acid red 151). Cobalt oxide nanoparticles (NPs) synthesized in the presence of SDBS as an anionic template showed the highest decolorization of 93% over acid red 151 after 120 min of illumination. The results showed a minimum bacterial inhibitory concentration for bacteria P. aeruginosa , and B. subtilis is about 31.25 µg/mL and 125 µg/mL, respectively. The Co/Co 3 O 4 nanocomposites exhibited vigorous antibacterial activity against gram-negative microorganisms mentioned like Pseudomonas aeruginosa .