Hydrothermal Preparation of Boehmite Nanorods by Selective Adsorption of Sulfate

Abstract

A facile hydrothermal method was developed to synthesize boehmite nanorods with a length of 50-2000 nm, a diameter of 6-20 nm, and a preferential growth along [100] by treating the Al(OH)(3) gel in acidified sulfate solutions at 240 degrees C. Studies on the hydrothermal treatment of Al(OH)(3) gel in sulfate solutions showed that the morphology and the composition of the hydrothermal products were connected with the sulfate concentration and the pH of the hydrothermal solution. The aspect ratio of the boehmite nanorods increased to 300 as the initial H(2)SO(4) concentration increased to 0.043 mol x L(-1), whereas boehmite nanorods and (H(3)O)Al(3)(SO(4))(2)(OH)(6) cubic particles coexisted in the case of the initial H(2)SO(4) concentration > or = 0.054 mol x L (-1). Sole boehmite nanoflakes with a diameter of about 50 nm were formed under alkaline conditions (pH 10.5) despite the existence of the sulfate. The chemical and Raman analyses indicated that SO(4)(2-) in acidified solutions adsorbed on the boehmite surface via H-bonds. On the basis of the above results, the growth of boehmite along the [100] direction was attributed to the selective adsorption of SO(4) (2-) on the (010) and (001) planes of boehmite.

Two-dimensional porous γ-AlOOH and γ-Al2O3 nanosheets: hydrothermal synthesis, formation mechanism and catalytic performance

“…6 Xia et al reported that inorganic hollow mesoporous monodisperse MnO/C microspheres are highly biocompatible and exhibit a high reversible specic capacity of 700 mA h g À1 at 0.1 A g À1 , and excellent cycling stability with 94% capacity retention. [8][9][10][11][12] Currently, various morphologic boehmite and g-Al 2 O 3 nanomaterials, such as nanotubes, 13 nanorods, 14 nanoplatelets and nanowires, 15 nanowire bunches, 16 microspheres, 8 hollow microspheres, 9 and owerlike 3D nanoarchitectures, 17,18 have been prepared. [8][9][10][11][12] Currently, various morphologic boehmite and g-Al 2 O 3 nanomaterials, such as nanotubes, 13 nanorods, 14 nanoplatelets and nanowires, 15 nanowire bunches, 16 microspheres, 8 hollow microspheres, 9 and owerlike 3D nanoarchitectures, 17,18 have been prepared.…”

Synthesis and Characterization of Boehmites Obtained from Gibbsite in Presence of Different Environments

“…1D materials includes fibers, spindles, needles, rods, wiskers and tubes [3][4][5][6][7][8][9][10][11][12][13][14][15] . Platelets, leaves and all kind of lamellar materials can be labeled as 2D materials 3,6,[16][17][18][19][20][21] .…”

Synthesization and crystallization mechanism of nano-scale γ-AlOOH with various morphologies

“…Nano-scale Al 2 O 3 is then obtained from γ-AlOOH by calcination. The hydrothermal reaction formula is as follows: Since Bugosh reported a hydrothermal method for the preparation of fibrous colloidal γ-AlOOH in 1961 [3], numerous hydrothermal growth technologies have been deployed to synthesize γ-AlOOH with different morphologies such as nanostrips [4], nanorods [5][6], and nanoflakes [7]. For example, some surfactants such as poly(ethylene oxide) [8] and organic solvents such as dimethylbenzene [9] have been adopted to obtain special needlelike γ-AlOOH.…”