Rare Earth Chalcogels NaLnSnS₄ (Ln = Y, Gd, Tb) for Selective Adsorption of Volatile Hydrocarbons and Gases

Abstract

The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS4, NaGdSnS4, and NaTbSnS4 is reported. Rare earth metal ions like Y3+, Gd3+, and Tb3+ react with the chalcogenide clusters [SnS4]4– in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m2·g–1 (NaYSnS4), 479 m2·g–1 (NaGdSnS4), and 354 m2·g–1 (NaTbSnS4). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2–50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO2 over CH4 or H2. The notable adsorption capacity for toluene (NaYSnS4: 1108 mg·g–1; NaGdSnS4: 921 mg·g–1; and NaTbSnS4: 645 mg·g–1) and high selectivity for gases (CO2/H2: 172 and CO2/CH4: 50 for NaYSnS4, CO2/H2: 155 and CO2/CH4: 37 for NaGdSnS4, and CO2/H2: 75 and CO2/CH4: 28 for NaTbSnS4) indicate potential future use of chalcogels in adsorption‐based gas or hydrocarbon separation processes.

Enhancement of CO2 and Toluene Adsorption on a Rare‐Earth Chalcophosphate Aerogel by Post Synthetic Modification with PdCl2

“…It can be seen that the parent aerogel showed a CO 2 capacity of 1.4 mmol · g –1 , which is very close to the value reported in a previous study under the same temperature ,. [22b], [22c] By doping the aerogel with a small amount of Pd, the CO 2 uptake had been apparently enhanced at all pressures up to 1.89 mmol · g –1 for 3 wt % Pd @ KY(P 2 S 6 ) 2 , 1.5 mmol · g –1 for 5 wt % Pd @ KY(P 2 S 6 ) 2 , and 1.63 mmol · g –1 for 1 wt % Pd @ KY(P 2 S 6 ) 2 (Figure ).…”

“…It can be seen that all the isotherms exhibited a sharp increase in adsorption amount. The saturated adsorption capacity of toluene on the parent aerogel in this study was estimated to be 703 mg · g –1 (8 mmol · g –1 ), which is close to the reported values of toluene adsorption on metal chalcogenide aerogels ,. [22b], [22c] Comparing with the parent aerogel, the PdCl 2 ‐functionalized aerogel exhibited increased saturated adsorption capacity for toluene at room temperature (Table ).…”

“…Consequently, the selectivity values would be declined. This phenomenon has been found in most metal chalcogenide aerogels , ,. [22c]…”

“…Most quaternary metal chalcogenide aerogels are synthesized using building blocks containing Ge, Sn, or Sb and limited to the transition metal ions. However, recently, we have extended this family to cover the rare earth chalcogel …”

Synthesis, Structure, and Properties of EuLnCuSe3 (Ln = Nd, Sm, Gd, Er)

“…Starting with the works of James A. Ibers [1], compounds of general composition A II Ln III BX 3 , where A is an alkaline earth metal or europium, Ln is an element of the 4f subgroup, B is copper or silver, and X is a chalcogen, increasingly attract researcher's attention [2][3][4][5]. The presence of 3d, 4f elements in the composition of quaternary compounds makes them promising materials in the field of catalysis [6,7], nonlinear optics [8][9][10][11][12][13][14], and thermoelectricity [15]. EuLnCuS 3 exhibit ferro-and ferrimagnetic transitions at temperatures 4.5-5.4 K [16].…”