Solar light driven photocatalytic degradation of methylene blue dye over Cu doped α-MnO2 nanoparticles

Abstract

Cu-α-MnO2 nanoparticles were synthesized by hydrothermal method and their potential application in the aqueous-based degradation of organic contaminants was examined under solar light. Cu doping increases the particle size and affects the morphology of MnO2. The Cu-doped α-MnO2 XRD pattern showed a tetragonal crystalline structure with a crystal size of ∼30nm. When compared to α-MnO2, which has a band gap energy of 1.58eV, the 6% Cu-doped α-MnO2 photocatalyst has a lower band gap energy (1.23eV). As a result, the light absorption was increased towards the visible spectrum. The considerable change in PL intensity of MnO2 observed after Cu doping. The findings show that a 6% Cu- α-MnO2 sample degrades methylene blue dye completely within 2 h. The improvement of the photocatalytic activity of the Cu-α-MnO2 nanoparticles was significantly influenced by the expanded light absorption range and effective charge separation. A variety of scavengers were employed to identify the active species by capturing the radicals and holes generated upon the photocatalytic degradation process.