Surfactant-Assisted Synthesis of Birnessite-Type MnO<sub>2</sub> Nanoflowers

Flower-like birnessite-type MnO 2 (Bir-MnO 2 ) was synthesized through decomposition of KMnO 4 under acid condition at 90 °C in open system. The addition of surfactant was a key factor for synthesis of Bir-MnO 2 at low temperature and ambient pressure. Crystal nucleus obtained via reaction between surfactant and KMnO 4 can catalyze decomposition of KMnO 4 , which led to the higher velocity of reaction. Reducibility of surfactant additional had an impact on yield and size of sample obtained. As-prepared sample with highest yield and smallest size was synthesized by using SOA as surfactant. Long reaction time and high reaction temperature were propitious to the growth of sample. The as-prepared samples were used to degrade rhodamine B (RhB), and the efficiency was different as the size of nanoflowers changed.