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

Abstract

Three-dimensional α-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 α-MnO2 microspheres with a diameter of about 2μm. Higher reaction temperature (80°C) leads to a higher aspect ratio of the nanorods on the surface of dandelion-like MnO2. The catalytic activities of the prepared α-MnO2 microspheres were explored by using toluene combustion as a probe reaction. The α-MnO2 microspheres with the shortest nanorods obtained at 40°C has higher catalytic activity than that of its counterpart with longer nanorods prepared at higher temperature (60°C and 80°C), owing to the highest oxygen vacancy defects concentration, lowest reducibility and highest specific surface area.