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 ~ 450 nm for pure, and ~ 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. [ABSTRACT FROM AUTHOR]