Influence of solvent on porosity and microstructure of an yttrium based aerogel

Abstract

Monolithic yttrium-based aerogels and xerogels were prepared by the epoxide addition method. The effects of changing both the gelation solvent and the yttrium salt precursor in the reaction were investigated. The porous morphology of the resulting aerogel materials was investigated using gas adsorption/desorption analysis, scanning electron microscopy and transmission electron microscopy. The solvent in which the aerogels were formed was found to significantly impact the porous structure and physical morphology of these materials. The counterion used to synthesize the gels also had a profound impact on gel formation. The chloride salt precursor gave successful gels while the nitrate salt gave only precipitates. The yttrium-based xerogels synthesized were annealed at various temperatures in static air, nitrogen, and oxygen atmospheres. The annealed materials were analyzed using powder X-ray diffraction. The amorphous as-synthesized material is found to form the stoichiometric yttrium oxide by way of an oxygen deficient yttrium oxide species which is black in color.

Printed aerogels: chemistry, processing, and applications

“…The formation of the gels can be divided into two types, one being the classic 'sol-gel method' starting from molecular precursors, 26 and the other being the 'colloidal dispersion method' starting from pre-formed nano-scale materials such as nanoparticles, nanotubes, nanowires, and nanosheets. 71 The sol-gel method is generally used to prepare inorganic oxide, [72][73][74] organic, 6,[75][76][77] and chalcogenide 78,79 aerogels, and always uses organic alkoxides, 73 metal chlorides, 74,80 nitrates, 81 small organic molecules, 75,76 biopolymers, 6 or prepolymerized molecules 82 as the molecular precursor. Depending on the precursors used, the chemical reactions and gelation mechanisms vary.…”

Synthesis, characterization and mechanism of formation of carbon aerogels incorporated with highly crystalline lanthanum oxychloride particles

“…PO (C 3 H 6 O) is well known as a proton (H + ion) scavenger and gelling agent to prepare metal oxide aerogels without using alkoxide. 25 When PO was added to a mixture of R, F, LaCl 3 and H 2 O, the HCl in the solution was rapidly consumed by the ringopening reaction of PO (see eqn (3)). At the same time, the pH of the mixture increased, which promoted the formation of the La(OH 2 ) 4 (OH) 3 product of reaction shown in eqn (2) and of wet La-doped RF gels.…”

Analysis of products formed in hydrothermal processing of yttrium chloride in the presence of complexing agent (citric acid)

“…Наиболее часто для синтеза подобных соединений иттрия используют нитраты и хлориды иттрия [1][2][3][4][5][6]. При этом синтез проводят как в условиях близких к атмосферным [1][2][3], так и в условиях гидротермального синтеза под вакуумом при повышенной температуре [4][5][6]. Следует отметить, что именно соединения, полученные из хлорида иттрия, проявляют тенденцию к формированию чёткой структуры субмикронных размеров [4].…”