The effect of pH and anions on the anisotropic growth of MnO2

Abstract MnO 2 with different morphologies was controllably synthesized. The co-effect of some anions (SO 4 2− , NO 3 − , PO 4 3− and Cl − ) and pH on the hydrothermal crystallization of MnO 2 was also investigated systematically. The final products were characterized by XRD, TEM and SEM. Based on our experimental results, we propose that the coarsening of MnO 2 can be impeded by anions. While when pH is dominant, this dissolution procedure can be accelerated and MnO 2 nanorod formed through dissolution–recrystallization process. The present work may provide a new sight into the anisotropic growth of MnO 2 .