Investigation of the interaction between adsorbed water and various morphologies of boehmite nanoparticles prepared by continuous supercritical hydrothermal synthesis

• Published in: The Journal of supercritical fluids Vol. 193; p. 105829
• Main Authors: Peigney, Erwan, Poulon-Quintin, Angéline, Cavarroc, Marjorie, Aubert, Guillaume, Duttine, Mathieu, Sarroste, Christine Labrugère, Aymonier, Cyril
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023; Elsevier
• Subjects: Chemical Sciences; Continuous supercritical hydrothermal synthesis; Material chemistry; pH-dependent morphology; Supercritical water; Synthetic boehmite nanoparticles; Water and nitrate adsorption; Synthetic boehmite nanoparticles; Continuous supercritical hydrothermal synthesis; pH-dependent morphology; Water and nitrate adsorption; Supercritical water
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2022.105829

Boehmite applications are often subject to specific characteristics in terms of morphologies and surface properties. The versatile continuous supercritical hydrothermal method allows synthesizing various boehmite morphologies from rhombic to hexagonal platelet-like nanoparticles depending on the preferential adsorption of part of the precursor after transformation species on the (020) surface resulting in a preferential growth along [001] and mostly [100] directions. This adsorption on surface free sites plays the role of morphology stabilizer and results in the reduction of adsorbed water. The interaction between adsorbed water and the boehmite morphology depends on various parameters: 1) the structure order of boehmite as exhibited by XPS analysis associated with 1H Solid-State NMR spectroscopy and, 2) the number of available free sites, which tend to be filled by the adsorption of nitrates as observed by Raman spectroscopy. [Display omitted] •Various boehmite morphologies are produced by continuous supercritical hydrothermal syntheses.•Boehmite nanoparticles tend to have a large excess of adsorbed water.•The adsorbed water content is correlated to size, morphology, structure order and adsorption of other species.