Titre :

Efficiency of Cu and Pd substitution in Fe-based perovskites to promote N 2 formation during NH 3 selective catalytic oxidation (NH 3 -SCO)

Auteur(s) :

Li, Peixin [Auteur]
Zhang, Runduo [Auteur]
Liu, Ning [Auteur]
Royer, sebastien [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]

Titre de la revue :

Applied Catalysis B. Environmental

Numéro :

203

Pagination :

174-188

Date de publication :

2017-04

Discipline(s) HAL :

Chimie/Catalyse

Résumé en anglais : [en]

Iron-based perovskites, of LaFe1-xB′xO3-δ (B′ = Cu, Pd) formula, are proposed as effective materials for the ammonia selective catalytic oxidation to nitrogen (NH3-SCO). Effects on N2 yield, of copper or palladium substitutions ...
Lire la suite >Iron-based perovskites, of LaFe1-xB′xO3-δ (B′ = Cu, Pd) formula, are proposed as effective materials for the ammonia selective catalytic oxidation to nitrogen (NH3-SCO). Effects on N2 yield, of copper or palladium substitutions in B position, and of perovskite dispersion over Al2O3 support, are reported. Copper and palladium substitution in perovskite lattice significantly promotes the NH3 conversion rate, owing to the outstanding redox capacity displayed by the substituted compositions at low temperature (T < 300 °C). While N2 yield decreases upon Cu-doping, it retains as high as 80–90% over Pd-containing catalysts. Copper substitution enhances low-temperature oxygen mobility, which is favorable to Nsingle bondH bond fracture of adsorbed −ONH3 species that results in high NO formation. Palladium substitution results in an opposite effect, and high selectivity towards N2 is obtained. Additionally, N2 yield is significantly improved at high temperature, when perovskite active phase is dispersed over Al2O3 support. Combining in-situ DRIFTS and density functional theory (DFT) calculations, NH3-SCO to N2 reaction pathway over Fe-based perovskites is proposed to follow an Eley-Rideal (E-R) mechanism, during which gaseous NH3 reacts with adsorbed −ONH2 species to form surface diazo species (single bondNdouble bondNsingle bond). For LaFeO3, the rate-determining step is the −ON2H2 to −ON2H reaction (overcoming an energy barrier of 3.48 eV), while for LaFe0.95Pd0.05O3, the rate-determining step is Osingle bondN bond cleavage (energy barrier of 1.55 eV) that explains then higher N2 yield measured for the Pd-containing perovskite catalyst.Lire moins >

Langue :

Anglais

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

ENSCL
CNRS
Centrale Lille
Univ. Artois
Université de Lille

Collections :

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

Équipe(s) de recherche :

Matériaux pour la catalyse (MATCAT)

Date de dépôt :

2019-09-25T14:37:48Z