Facile and rapid synthesis of nanoplates Mg(OH)₂ and MgO via Microwave technique from metal source: structural, optical and dielectric properties

Magnesium hydroxide and magnesium oxide nanostructures have been prepared by microwave/hydrothermal technique using magnesium metal in hydrogen peroxide (H₂O₂). The applied power of the microwave was 700 W for 10 min at 145 °C. The method produced Mg(OH)₂ powder as a base material for MgO by calcinations at 550 °C for 2 h. X-ray diffraction data confirms the microwave production of Mg(OH)₂ and (MgO) through the agreement with the standard JCDPS cards. Scanning electron microscopy shows nanoplates morphology for Mg(OH)₂ and large-scale nanoplates with a hexagonal shape for MgO. The fundamental direct optical band gap of Mg(OH)₂ equals 5.8 eV while for MgO equals 5.2 eV from the analysis of diffused reflectance data. MgO has higher dielectric constant than Mg(OH)₂ at the higher frequencies. AC electrical conductivity increases with increasing the applied frequency for both materials. The microwave-hydrothermal technique shows a promising method for production of magnesium compounds from magnesium metal which can be used in different aspects such as catalysis, wastewater treatment, pharmaceutical and coated materials.