Nanoscale hydration in layered manganese oxides [Elektronisk resurs]
-
Cheng, Wei (författare)
-
Lindholm, Jerry (författare)
-
Holmboe, Michael (författare)
-
Luong, N. Tan (författare)
-
Shchukarev, Andrey (författare)
-
Ilton, Eugene S. (författare)
-
Hanna, Khalil (författare)
-
Boily, Jean-Francois (författare)
-
Umeå universitet Teknisk-naturvetenskapliga fakulteten (utgivare)
- Publicerad: American Chemical Society (ACS), 2021
- Engelska.
-
Ingår i: Langmuir. - 0743-7463. ; 37:2, 666-674
-
Läs hela texten
-
Läs hela texten
-
Läs hela texten
- Relaterad länk:
-
http://www.umu.se/ (Värdpublikation)
Sammanfattning
Ämnesord
Stäng
- Birnessite is a layered MnO 2 mineral capable of intercalating nanometric water films in its bulk. With its variable distributions of Mn oxidation states (Mn IV , Mn III , and Mn II ), cationic vacancies, and interlayer cationic populations, birnessite plays key roles in catalysis, energy storage solutions, and environmental (geo)chemistry. We here report the molecular controls driving the nanoscale intercalation of water in potassium-exchanged birnessite nanoparticles. From microgravimetry, vibrational spectroscopy, and X-ray diffraction, we find that birnessite intercalates no more than one monolayer of water per interlayer when exposed to water vapor at 25 °C, even near the dew point. Molecular dynamics showed that a single monolayer is an energetically favorable hydration state that consists of 1.33 water molecules per unit cell. This monolayer is stabilized by concerted potassium–water and direct water–birnessite interactions, and involves negligible water–water interactions. Using our composite adsorption–condensation–intercalation model, we predicted humidity-dependent water loadings in terms of water intercalated in the internal and adsorbed at external basal faces, the proportions of which vary with particle size. The model also accounts for additional populations condensed on and between particles. By describing the nanoscale hydration of birnessite, our work secures a path for understanding the water-driven catalytic chemistry that this important layered manganese oxide mineral can host in natural and technological settings.
Ämnesord
- Natural Sciences (hsv)
- Earth and Related Environmental Sciences (hsv)
- Geochemistry (hsv)
- Naturvetenskap (hsv)
- Geovetenskap och miljövetenskap (hsv)
- Geokemi (hsv)
Genre
- government publication (marcgt)
Inställningar
Hjälp
Ingår i annan publikation. Gå till titeln
Langmuir