Mesoporous β-MnO2 nanoparticles were synthesized by a template-free low-temperature crystallization of Mn4+ precursors (low-crystallinity layer-type Mn4+ oxide, c-distorted H+-birnessite) produced by the reaction of MnO4- and Mn2+. The Mn starting materials, pH of the reaction solution, and calcination temperatures significantly affect the…[Read more]