Effect of cobalt doping on the structural, optical and antibacterial properties of α-MnO2 nanorods

In this work, we have successfully synthesized pure and Cobalt (2.5% and 5%) doped-MnO2 nanorods via a simple hydrothermal route. The morphological, structural, optical, and antibacterial effects, were studied using advanced analytical techniques. The grain sizes of as-prepared nanorods, were calculated in the range of 21-26 nm. The UV-Visible absorption spectroscopy shows a broad absorption band, centered at similar to 450 nm for pure, and similar to 465 nm for cobalt-doped MnO2 nanorods, respectively. The reduction in band gap was observed from 2.36 to 1.96 eV with the increase in the dopant concentration. The antimicrobial activities of synthesized samples were studied against gram-negative (E. coli and P.aeruginosa) bacteria and a gram-positive (S.aureus) bacteria. The antimicrobial studies show inhibition zones in the range of 9-16 mm for pure and cobalt-doped MnO2. The maximum inhibition zone (MIC) was observed for 5% Co-MnO2 doping against E. coli. We believe that the synthesized nanorods can be used as antimicrobial agent, and that could be used for antibacterial drug applications.