Titre :

The Unexpected Role of Fluorine in the Band Gap Narrowing of Silver Niobium and Tantalum Pyrochlore Oxyfluorides.

Auteur(s) :

Moussa, Celine [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Pourpoint, Frederique [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Saitzek, Sebastien [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Famprikis, T. [Auteur]
Delft University of Technology [TU Delft]
Roussel, Pascal [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Kabbour, Houria [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Boivin, Edouard [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181

Titre de la revue :

Inorg Chem

Nom court de la revue :

Inorg Chem

Date de publication :

2025-02-22

ISSN :

1520-510X

Mot(s)-clé(s) en anglais :

Chemical structure
Electrical conductivity
Electrodes
Fluorine
Materials

Discipline(s) HAL :

Chimie/Chimie inorganique

Résumé en anglais : [en]

Mixed anion compounds have attracted growing interest in solid-state chemistry as a way to tailor physical properties. In this work, we synthesized new silver niobium and tantalum pyrochlore oxyfluorides by an ion-exchange ...
Lire la suite >Mixed anion compounds have attracted growing interest in solid-state chemistry as a way to tailor physical properties. In this work, we synthesized new silver niobium and tantalum pyrochlore oxyfluorides by an ion-exchange reaction from Na2M2O5F2 (M = Nb or Ta). Instead of a classical Na+/Ag+ cation exchange, a less conventional dual cation and anion exchange reaction (2 Na+ + F–)/(Ag+ + H2O) takes place. Indeed, chemical and thermal analyses, as well as Rietveld refinement and 19F NMR, reveal the formation of AgTa2O5F·H2O and Na0.4Ag0.8Nb2O5F1.2·0.8H2O leading to a significant band gap narrowing of approximately 0.4 eV, as determined by diffuse reflectance spectroscopy. DFT calculations show that Ag 4d–O 2p states are located at the edge of the valence band and that the presence of fluorine in the coordination sphere of Ag promotes the hybridization and hence contributes to the band gap narrowing.Lire moins >

Langue :

Anglais

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

Université de Lille
CNRS
Centrale Lille
ENSCL
Univ. Artois

Collections :

• Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181

Équipe(s) de recherche :

RMN et matériaux inorganiques (RM2I)

Date de dépôt :

2025-03-15T22:09:11Z
2025-03-26T07:32:35Z