Structural and Morphological Features of Disperse Alumina Synthesized Using Aluminum Nitrate Nonahydrate

详细信息    查看全文

• 作者：Ivan F. Myronyuk ; Volodymyr I. Mandzyuk ; Volodymyr M. Sachko…
• 关键词：Aluminum nitrate nonahydrate ; Aluminum hydroxide ; Alumina ; Nanoparticle morphology ; Aggregate texture
• 刊名：Nanoscale Research Letters
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：11
• 期：1
• 全文大小：1,735 KB
• 刊物主题：Nanotechnology; Nanotechnology and Microengineering; Nanoscale Science and Technology; Nanochemistry; Molecular Medicine;
• 出版者：Springer US
• ISSN：1556-276X

文摘

Transformation of Al(NO₃)₃∙9H₂O (upon heating in the range of 20–1200 °C) into blends of amorphous and crystalline boehmite (210–525 °C), amorphous alumina and crystalline γ-Al₂O₃ (850 °C), and crystalline α-Al₂O₃ (1100 °C) was analyzed using X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), infrared (IR) spectroscopy, thermogravimetry, and low-temperature nitrogen adsorption. Boehmite consists of nanoparticles of 6–10 nm in diameter, and part of them has crystalline structure observed in HRTEM images, despite they are XRD amorphous. The nanoglobules are surrounded by amorphous aluminum hydroxide with chains of –AlO(H)–O–AlO(H)– of 1–5 nm in length. Heating of samples at 350–525 °C gives mesoporous aluminum hydroxide with a relatively narrow pore size distribution. An increase in calcination temperature to 850 °C decreases the porosity of alumina composed of amorphous and crystalline (γ-Al₂O₃) phases. Calcination at 1100 °C gives α-Al₂O₃ with strongly decreased porosity of aggregates.