Exfoliation of layered yttrium hydroxide by rapid expansion of supercritical suspensions

Supercritical CO2 Directional-Assisted Synthesis of Low-Dimensional Materials for Functional Applications

Supercritical CO2 (SC CO2 ), as one of the unique fluids that possess fascinating properties of gas and liquid, holds great promise in chemical reactions and fabrication of materials. Building special nanostructures via SC CO2 for functional applications has been the focus of intense research for the past two decades, with facile regulated reaction conditions and a particular reaction field to operate compared to the more widely used solvent systems. In this review, the significance of SC CO2 on fabricating various functional materials including modification of 1D carbon nanotubes, 2D materials, and 2D heterostructures is stated. The fundamental aspects involving building special nanostructures via SC CO2 are explored: how their structure, morphology, and chemical composition be affected by the SC CO2 . Various optimization strategies are outlined to improve their performances, and recent advances are combined to present a coherent understanding of the mechanism of SC CO2 acting on these functional nanostructures. The wide applications of these special nanostructures in catalysis, biosensing, optoelectronics, microelectronics, and energy transformation are discussed. Moreover, the current status of SC CO2 research, the existing scientific issues, and application challenges, as well as the possible future directions to advance this fertile field are proposed in this review.

The first amorphous and crystalline yttrium lactate: synthesis and structural features

The synthesis and crystal structure of the first molecular yttrium lactate complex, Y(Lac)₃(H₂O)₂, is reported, where the coordination sphere of yttrium is saturated with lactate ligands and water molecules, resulting in a neutral moiety. In Y(Lac)₃(H₂O)₂, hydrogen bonding between α-hydroxy groups and water molecules allows for the formation of 2D layers. A subtle variation in synthetic conditions, i.e. a slight increase in pH (5.5 instead of 4.5) promoted the formation of a semi-amorphous fibrous material with a presumed chemical composition of Y₄(OH)₅(C₃H₅O₃)₇·6H₂O. The flattened fibres in this material are responsible for its good flexibility and foldability.

The synthesis and crystal structure of the first molecular yttrium lactate complex, Y(Lac)₃(H₂O)₂, is reported, where the coordination sphere of yttrium is saturated with lactate ligands and water molecules, resulting in a neutral moiety.