Stability of Iodine Species Trapped in Titanium-Based MOFs: MIL-125 and MIL-125_NH 2 .

Autor: Andrade PHM; Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille - Sciences et Technologies, Villeneuve d'Ascq, 59655, France.; Departamento de Engenharia Metalúrgica e de Materiais (DEMET), Departamento de Física (DF), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil., Dhainaut J; Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, Lille, F-59000, France., Volkringer C; Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, Lille, F-59000, France., Loiseau T; Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181, Lille, F-59000, France., Moncomble A; Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille - Sciences et Technologies, Villeneuve d'Ascq, 59655, France., Hureau M; Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille - Sciences et Technologies, Villeneuve d'Ascq, 59655, France., Moissette A; Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille - Sciences et Technologies, Villeneuve d'Ascq, 59655, France.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Aug; Vol. 20 (35), pp. e2400265. Date of Electronic Publication: 2024 Apr 25.
DOI: 10.1002/smll.202400265
Abstrakt: Two titanium-based MOFs MIL-125 and MIL-125_NH 2 are synthesized and characterized using high-temperature powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), N 2 sorption, Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), and electron paramagnetic resonance (EPR). Stable up to 300 °C, both compounds exhibited similar specific surface areas (SSA) values (1207 and 1099 m 2  g -1 for MIL-125 and MIL-125_NH 2 , respectively). EPR signals of Ti 3+ are observed in both, whith MIL-125_NH 2 also showing ─NH 2 ●+ signatures. Both MOFs efficiently adsorbed iodine in continuous gas flow over five days, with MIL-125 trapping 1.9 g.g -1 and MIL-125_NH 2 trapping 1.6 g.g -1 . MIL-125_NH 2 exhibited faster adsorption kinetics due to its smaller band gap (2.5 against 3.6 eV). In situ Raman spectroscopy conducted during iodine adsorption revealed signal evolution from "free" I 2 to "perturbed" I 2 , and I 3 - . TGA and in situ Raman desorption experiments showed that ─NH 2 groups improved the stabilization of I 3 - due to an electrostatic interaction with NH 2 ●+ BDC radicals. The Albery model indicated longer lifetimes for iodine desorption in I 2 @MIL-125_NH 2 , attributed to a rate-limiting step due to stronger interaction between the anionic iodine species and the ─NH 2 ●+ radicals. This study underscores how MOFs with efficient charge separation and hole-stabilizer functional groups enhance iodine stability at higher temperatures.
(© 2024 The Authors. Small published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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