Microwave and Induction Heating-Assisted Biosynthesis of 12CaO 7Al2O3 Electride from Aloe Vera Leaf Extract

Abstract

The white powders used as precursor powders for the synthesis of 12CaO×7Al₂O₃ electride (C₁₂A₇:e^-) were prepared by biosynthesis method using Aloe vera extract and microwave assisted synthesis. The C₁₂A₇:e^- crystals were synthesized by induction heating process under a reducing atmosphere at different times of 3, 4 and 5 min. The structure of C₁₂A₇:e^- powders was characterized by X-ray diffraction. The XRD analysis revealed that pure C₁₂A₇:e^- powders were obtained from white precursor powders with an induction heating process time of 5 min. To confirm that the white precursor powders were transformed into C₁₂A₇:e^- after induction heating process for 3, 4 and 5 min, the optical absorption spectra of powders were investigated by an UV-Vis diffuse reflectance spectrometer in the wavelength range of 200 – 800 nm. The results show the optical absorption bands at 2.8 eV for the white precursor powders with induction heating time of 3, 4 and 5 min. This is due to the C₁₂A₇ was transformed into electride (C₁₂A₇:e^-). Therefore, the results on the optical absorption spectra are in good agreement with the XRD results.