Mesoporous α-MnO2 microspheres with high specific surface area: Controlled synthesis and catalytic activities

Three-dimensional alpha-MnO2 microspheres with high specific surface area were synthesized via a homogeneous catalytic reaction using Ag+ as catalyst at relatively low temperature. The reaction temperature was found to play an important role in controlling the microstructures of alpha-MnO2 microspheres with a diameter of about 2 mu m. Higher reaction temperature (80 degrees C) leads to a higher aspect ratio of the nanorods on the surface of dandelion-like MnO2. The catalytic activities of the prepared alpha-MnO2 microspheres were explored by using toluene combustion as a probe reaction. The alpha-MnO2 microspheres with the shortest nanorods obtained at 40 degrees C has higher catalytic activity than that of its counterpart with longer nanorods prepared at higher temperature (60 degrees C and 80 degrees C), owing to the highest oxygen vacancy defects concentration, lowest reducibility and highest specific surface area. (C) 2015 Elsevier B.V. All rights reserved.