<p>The present study effectively generated manganese dioxide nanoparticles through the use of both chemical and green synthesis methods. In the green synthesis, Musa acuminata flower extract was used as a reducing and stabilizing agent. The synthesised nanoparticles were examined using XRD, SEM, FT-IR, UV–visible spectroscopy, and EDAX techniques. The photocatalytic efficiency of green and chemically prepared MnO₂ NPs were examined in this specific study. It takes work to lower the toxicity of MnO₂ NPs in an environmentally responsible way when they are produced. The photocatalytic efficiency of several simple oxides of transition metals have also been examined by a study of their band gap energies when exposed to the dye Methylene blue (MB), which is a prominent water pollutant produced by the textile industry. The dye used in all of the photocatalytic studies was Methylene blue (MB).</p>