Morphology-controlled synthesis and microwave absorption properties of β-MnO2 microncube with rectangular pyramid

beta-MnO2 microncube is a novel morphology of microncube with rectangular pyramid. It has been synthesized for the first time via a simple aqueous chemical route under hydrothermal conditions without any templates. When the reaction time is increased from 1 h to 10 h, the crystal type changed from gamma-MnO2 to beta-MnO2 and the morphology changed from an urchin-like shape to a microncube with rectangular pyramid. We propose a possible growth mechanism for intrinsic structural growth mechanism, the evolution process of the beta-MnO2 structure is proposed to involve two main stages. Besides, the electromagnetic properties of the synthesized beta-MnO2 were investigated. It shows that beta-MnO2 has certain dielectric loss properties and an effective absorption bandwidth (reflection loss lower than - 10 dB) of 3.5 GHz was achieved from the beta-MnO2/paraffin wax composite. (C) 2015 Elsevier Inc. All rights reserved.