Transition aluminas, and especially the gamma type, are largely used as catalyst supports in refining and petrochemicals. Most studies focus on properties resulting from material texture and casting (specific surface, porous volume, pore shape and diameter). However, surface properties of alumina should be considered as well, as the catalytic activity is tightly related to the structure of exposed crystalline faces. As γ-alumina results from controlled thermal treatment of boehmite γ-AlOOH by a topotactic transformation, the nature of exposed crystalline planes is related to the starting material. Therefore, the synthesis of the oxihydroxide γ-AlOOH, and especially size and shape of these particles, is critical in determining the relevant surface properties.

We present an innovating way to control morphology of boehmite nanoparticles synthesized by soft chemistry routes. The use of organic complexing agents such as polyols, carboxylates, and hydroxycarboxylates during synthesis causes a modification of usual morphologies observed, specifically resulting in an observed increase of (101) faces (from 45% without complexing agent to 65% in the presence of tartrate). For instance in the case of polyols, we show that the variation of nanoparticles aspect ratio depends on polyol carbon chain length and stereochemistry.Material characterizations were performed using novel methods such as x-ray diffraction powder pattern simulation and zetametry in addition to transmission electron microscopy. Crystal growth mechanisms were investigated through adsorption isotherms, solid-state NMR spectroscopy and molecular simulation. We will also present our first results concerning catalytic properties of γ-alumina synthesized from these boehmite materials. Finally, we expect that this method will provide a promising way for the design of γ-alumina catalyst supports.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/11484 must be provided.

1. Thermal Stability of TiO₂ Nanoparticles with Controlled Size and Shape: Toward Use of a New Catalyst Supports
2. Structural and morphological control of manganese oxide nanoparticles by aqueous precipitation. Toward improved electrochemical behavior versus lithium.
3. Soft synthesis conditions of original shaped TiO2 nanoparticles from TiCl3
4. A Novel Method for the Determination of Nanoparticle Size and Shape based on X-Ray Powder Pattern Simulation: Application to Boehmite AlOOH
5. Some relevant parameters for the design of nanoparticles by aqueous chemistry