Electrochemical investigations of Mn-doped ZnO/rGO nanoparticles electrode material for supercapacitor application and its enhanced antimicrobial activity

Chemically prepared Mn-doped ZnO/rGO nanoparticles are used to investigate the structural, optical, electrochemical and antimicrobial properties. The X-ray diffraction studies show the wurtzite geometry of the materials. The Debye–Scherrer’s formula, Williamson–Hall equation and Halder–Wagner methods are employed to study the crystallite size and strain of the material. The addition of Mn and rGO reduces the optical transmission and the band gap of the material ranges from 3.084 to 3.190 eV, and the prepared semiconducting materials are positive type in nature. The addition of Mn and rGO enhances the charge carrier concentration of the prepared material. As a supercapacitor electrode, the electrochemical properties of the materials are analyzed by the cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) methods. Mn-doped ZnO/rGO has high specific capacitance as compared with Mn-doped ZnO and undoped ZnO nanoparticles. The anti-bacterial activity against both gram-positive and gram-negative is reported. The Mn-doped ZnO/rGO shows higher electrochemical and antimicrobial properties as compared with undoped and Mn-doped ZnO nanoparticles. Due to the enhanced charge carrier concentrations Mn-doped ZnO nanoparticles shows excellent electrochemical and antimicrobial properties as compared with undoped and Mn-doped ZnO.