Evolution of Correlated Morphological and Structural Disorder in Boehmite-Derived Alumina with Progressive Calcination

This study explores the morphological and structural transformation of boehmite (AlOOH) into transition aluminas during calcination, a pathway crucial for diverse industrial applications. The primary focus is on the topotactic transformation of boehmite into gamma-Al2O3 and its subsequent transitions into higher temperature polymorphs, culminating in alpha-Al2O3. Utilizing a combination of in situ X-ray diffraction, in situ and ex situ transmission electron microscopy, 27Al solid-state nuclear magnetic resonance, thermogravimetric analysis, nitrogen physisorption, and mercury porosimetry, this work provides insights into the morphological and structural reordering during the calcination process. Furthermore, the study highlights the significant impact of thermal processing on the morphological evolution of boehmite and transition aluminas, characterized by changes in pore structure sizes and shapes. These findings offer valuable insights for optimizing the properties of alumina-based materials for specific applications. This study explores the transformation of boehmite (AlOOH) into transition aluminas during calcination, emphasizing on the progression from gamma-Al2O3 to alpha- Al2O3. Through a combination of in-situ techniques, the research elucidates the pseudomorphic retention of structure during initial dehydration and successive structural ordering at higher temperatures. The results highlight the influence of thermal processing on pore structure development, contributing to our understanding of boehmite derived alumina for industrial applications. image