Isopropanol assisted preparation of α-Al2O3 nanoparticles and its surface charge investigation

The crystal and particle size distribution of α-alumina (α-Al₂O₃) nanoparticles is increasingly important for their potential application. However, it is difficult to produce α-Al₂O₃ nanoparticles due to the high activation energy barrier making it difficult to obtain a pure α-Al₂O₃. In this paper, α-Al₂O₃ nanoparticles with an average size of 60 nm in width and about 100–300 nm in length were prepared using isopropanol through thermal treatment at 1200 °C, accompanied by a minor fraction of the θ phase. Addressing the challenge of achieving pure phase α-Al₂O₃, Density Functional Theory (DFT) calculation was conducted to explore the energy landscape similarity between the θ and α crystal phases. The results provided valuable insights into obstacles associated with obtaining pure α-Al₂O₃, enlightening the relationship between surface electronegativity and crystal phases. Furthermore, X-ray Photoelectron Spectroscopy and electrochemical tests were employed to demonstrate that the α phase could enhance the surface electronegativity of Al₂O₃. This comprehensive study not only encompasses the synthesis of Al₂O₃ nanoparticles but also elucidates the distinctions between α and θ phases. These results offer valuable insights into methods optimizing for the synthesis of pure phase α-Al₂O₃.