Novel puffball–γ–MnO 2 nanoparticles: preparation, Cu 2+ –modification, and application in photocatalytic decolorization of dyes

Puffball-like γ–MnO2 nanoparticles of about 40 ± 1 nm size, having a unique morphology and high BET surface area were synthesized under reflux conditions and subsequently modified with Cu2+. The as-synthesized nanoparticles were systematically characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT–IR), N2 adsorption–desorption isotherms (BET) and energy dispersive X-ray analysis (EDX). The puffball–γ–MnO2 nanoparticles showed remarkable photocatalytic activity in treatment of wastewater and decolorization of dyes, especially Rhodamine 6G in presence of ultraviolet light–emitting diodes (UV–LEDs) irradiation. Under the optimized conditions, 91.5% decolorization was obtained for 200 mL of a 5 ppm solution of Rhodamine 6G within 40 min. It was also found that inclusion of Cu2+ has a significant positive effect (up to 17%) on the performance of these newly devised nanoparticles.