Improved NOx Storage/Release Properties of Ceria-Based Lean NOx Trap Compositions with MnOx Modification
- Resource Type
- Authors
- Juan Carlos Martínez-Munuera; Javier Giménez-Mañogil; Thomas Harmening; Marcos Schöneborn; Avelina García-García
- Source
- Materials
Volume 12
Issue 13
Materials, Vol 12, Iss 13, p 2127 (2019)
RUA. Repositorio Institucional de la Universidad de Alicante
Universidad de Alicante (UA)
- Subject
- spinel
Thermal desorption spectroscopy
Spinel
chemistry.chemical_element
barium
02 engineering and technology
engineering.material
010402 general chemistry
lcsh:Technology
01 natural sciences
Catalysis
passive NOx adsorber
Adsorption
Ceria
Desorption
NO oxidation
NOx storage
General Materials Science
lcsh:Microscopy
Incipient wetness impregnation
NOx
lcsh:QC120-168.85
lean NOx trap
Manganese
Química Inorgánica
Lean NOx trap
lcsh:QH201-278.5
lcsh:T
Chemistry
Barium
Passive NOx adsorber
021001 nanoscience & nanotechnology
0104 chemical sciences
ceria
Chemical engineering
lcsh:TA1-2040
engineering
manganese
lcsh:Descriptive and experimental mechanics
lcsh:Electrical engineering. Electronics. Nuclear engineering
lcsh:Engineering (General). Civil engineering (General)
0210 nano-technology
lcsh:TK1-9971
- Language
- English
Ceria/spinel-based lean NOx trap compositions with and without barium were modified with MnOx via incipient wetness impregnation. The effect of the MnOx layer on the aged materials (850 °
C) as to the NOx storage and release properties was investigated via NOx adsorption (500 ppm NO/5% O2/balance N2) carried out at 300 °
C in a dual-bed with a 1% Pt/Al2O3 catalyst placed upstream of the samples to generate sufficient amounts of NO2 required for efficient NOx storage. Subsequent temperature programmed desorption (TPD) experiments were carried out under N2 from 300 °
C to 700 °
C. The addition of MnOx to the barium free composition led to a slightly reduced NOx storage capacity but all of the ad-NOx species were released from this material at significantly lower temperatures (&Delta
T &asymp
100 °
C). The formation of a MnOx layer between ceria/spinel and barium had a remarkable effect on ageing stability as the formation of BaAl2O4 was suppressed in favour of BaMnO3. The presence of this phase resulted in an increased NOx storage capacity and lower desorption temperatures. Furthermore, NOx adsorption experiments carried out in absence of the Pt-catalyst also revealed an unexpected high NOx storage ability at low NO2/NO ratios, which could make this composition suitable for various lean NOx trap catalysts (LNT) related applications.