Revisiting Metal-Organic Frameworks Porosimetry by Positron Annihilation: Metal Ion States and Positronium Parameters

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

Abstract

Metal-organic frameworks (MOFs) stand as pivotal porous materials with exceptional surface areas, adaptability, and versatility. Positron Annihilation Lifetime Spectroscopy (PALS) is an indispensable tool for characterizing MOF porosity, especially micro- and mesopores in both open and closed phases. Notably, PALS offers porosity insights independent of probe molecules, which is vital for detailed characterization without structural transformations. This study explores how metal ion states in MOFs affect PALS results. We find significant differences in measured porosity due to paramagnetic or oxidized metal ions compared to simulated values. By analyzing CPO-27(M) (M = Mg, Co, Ni), with identical pore dimensions, we observe distinct PALS data alterations based on metal ions. Paramagnetic Co and Ni ions hinder and quench positronium (Ps) formation, resulting in smaller measured pore volumes and sizes. Mg only quenches Ps, leading to underestimated pore sizes without volume distortion. This underscores the metal ions’ pivotal role in PALS outcomes, urging caution in interpreting MOF porosity.

Details

OriginalspracheEnglisch
Seiten (von - bis)4560-4567
Seitenumfang8
FachzeitschriftJournal of Physical Chemistry Letters
Jahrgang15
Ausgabenummer17
PublikationsstatusVeröffentlicht - 2 Mai 2024
Peer-Review-StatusJa

Externe IDs

PubMed 38638089