Preparation and Optimization of MnO2 Nanoparticles

Manganese dioxide (MnO2) is one of the commonly applied inorganic material which is gaining increasing attentions in recent years. However, preparation and optimization of MnO2 nanoparticles have rarely been studied by previous studies, making the mechanisms responsible for preparation of MnO2 remaining largely unknown. Here in this study, we synthesized MnO2 through reduction of potassium permanganate (KMnO4) using different reductants, including protein, polymers and small molecule organic acids. It was suggested that, stable MnO2 nanoparticles can only be obtained in balanced synthesis/stabilization process which requires the reductant to have proper reducibility and stabilization ability at the right charge ratios. Our results concluded that, among these materials, polyvinylpyrrolidone (PVP) K30 showed the best performance at the charge ratio of 8/3 (w/w, PVP K30 to KMnO4, under given reaction conditions, which resulted in nanoparticles (hydrodynamic size: 79.72±31.53) with high stability and well dispersity, which was then selected as the optimal formulation.