Surfactant‐Assisted Synthesis of Alumina with Hierarchical Nanopores

Abstract

Using surfactant‐assisted synthesis, aluminas with hierarchical nanopores are produced. The hierarchical structures are composed of mesopores of 4 nm diameter, and macropores with diameters of about 300 nm. The structures were found to be stable to the thermal removal of the surfactant. Synthesis factors affecting the appearance of the hierarchically structured alumina material are presented. A potential mechanism for the formation of the uniquely structured aluminas is proposed.

Organic‐Additive‐Assisted Synthesis of Hierarchically Meso‐/Macroporous Titanium Phosphonates

“…This framework is quite similar to those of previously reported surfactant-assisted meso-/macrostructured metal oxide materials. [30,31] Moreover, careful examination of these SEM micrographs reveals that the pore wall of the large macropores in A-CD are separated by smaller spherical pores with the size of 50-100 nm, which thereby forms a two-scaled macroporous structure (Figure 1e). It is reminiscent of the hierarchically meso-/macroporous titanium phosphates synthesized in the presence of the polyethylene oxide surfactant Brij 56, [32] which indicates that the surfactant molecules are not necessary for the formation of the macrochannels, but the addition of a small amount of β-cyclodextrin could lead to the presence of secondary small-scaled macropores.…”

“…Figure 1 shows the representative SEM images of the obtained samples, which reveals macroporous structures in all the samples synthesized with and without organic additive assistance (sample prepared in the presence of EO 30 PO 34 only: A-poly; prepared in the presence of β-CD only: A-CD; prepared in the absence of organic additives: A-non). The macropores have a channel-like shape with a uniform distribution and diameters in the range 500-1000 nm.…”

Hierarchically structured meso-macroporous aluminosilicates with high tetrahedral aluminium content in acid catalysed esterification of fatty acids

“…Other one is related to post-synthesis treatments [29]. Lately, a self-formation phenomenon of porous hierarchy has been discovered [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. This new strategy is based on the very fast polymerisation of metal alkoxides in aqueous solution, yielding hierarchical meso-macroporous oxide and metallosilicate materials.…”

Simple preparation of silica and alumina with a hierarchical pore system via the dual-templating method

“…The functionality of alumina can be enhanced by adding mesoporous properties, such as a high surface area, large pore volume and uniform pore size. Several studies on ordered mesoporous alumina [12,13] and the synthesis of hierarchical alumina [14][15][16] have been reported; however, the macropores were not uniform in size and their packing was insufficient [14][15][16].…”