NO adsorption and decomposition on La2O3 studied by DRIFTS

Klingenberg, B.; Vannice, M. A.

doi:10.1016/s0926-3373(99)00003-x

Cited by 118 publications

(72 citation statements)

References 38 publications

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“…Another type of adsorbed nitrate, revealing vibrational features at 1530 and 1269 cm −1 can be assigned to monodentate nitrates [37]. Two characteristic vibrational modes of bidentate nitrates are also observed on the surface which are located at 1568 and 1246 cm −1 [35,36]. The vibrational bands at 1434, 1322 and 804 cm −1 in Fig.…”

Section: Resultsmentioning

confidence: 86%

“…Fig. 6c) samples at 323 K. FTIR spectra yield a convoluted set of bands corresponding to various types of nitrates and nitrites with different surface adsorption geometries [34][35][36][37][38][39][40]. Vibrational features appearing at 1649 and 1009 cm −1 are assigned to asymmetric and symmetric stretching modes of bridging nitrate species on the perovskite surface, respectively [34].…”

Section: Resultsmentioning

confidence: 99%

“…10 illustrates that on the pre-reduced surfaces, abundance of nitrite/nitrito species increases as evident from the relative strengthening of the vibrational frequencies at 1487, ∼1450 and 1330 cm −1 while nitrate-related vibrational features (e.g. 1567 and 1270 cm −1 ) attenuate in a relative fashion [35,36].…”

Section: No 2 Adsorption/desorption Behavior Of Perovskite Surfacesmentioning

confidence: 98%

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Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

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Vovk

et al. 2014

Applied Catalysis B: Environmental

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a b s t r a c tPerovskite-based materials (LaMnO 3 , Pd/LaMnO 3 , LaCoO 3 and Pd/LaCoO 3 ) were synthesized, characterized (via BET, XRD, Raman spectroscopy, XPS and TEM) and their NO x (x = 1,2) adsorption characteristics were investigated (via in-situ FTIR and TPD) as a function of the nature of the B-site cation (i.e. Mn vs Co), Pd/PdO incorporation and H 2 -pretreatment. NO x adsorption on of LaMnO 3 was found to be significantly higher than LaCoO 3 , in line with the higher SSA of LaMnO 3 . Incorporation of PdO nanoparticles with an average diameter of ca. 4 nm did not have a significant effect on the amount of NO 2 adsorbed on fresh LaMnO 3 and LaCoO 3 . TPD experiments suggested that saturation of fresh LaMnO 3 , Pd/LaMnO 3 , LaCoO 3 and Pd/LaCoO 3 with NO 2 at 323 K resulted in the desorption of NO 2 , NO, N 2 O and N 2 (without O 2 ) below 700 K, while above 700 K, NO x desorption was predominantly in the form of NO + O 2 . Perovskite materials were found to be capable of activating N-O linkages typically at ca. 550 K (even in the absence of an external reducing agent) forming N 2 and N 2 O as direct NO x decomposition products. H 2 -pretreatment yielded a drastic boost in the NO oxidation and NO x adsorption of all samples, particularly for the Cobased systems. Presence of Pd further boosted the NO x uptake upon H 2 -pretreatment. Increase in the NO x adsorption of H 2 -pretreated LaCoO 3 and Pd/LaCoO 3 surfaces could be associated with the electronic changes (i.e. reduction of B-site cation), structural changes (surface reconstruction and SSA increase), reduction of the precious metal oxide (PdO) into metallic species (Pd), and the generation of oxygen defects on the perovskite. Mn-based systems were more resilient toward B-site reduction. Pd-addition suppressed the B-site reduction and preserved the ABO 3 perovskite structure.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: No 2 Adsorption/desorption Behavior Of Perovskite Surfacesmentioning

confidence: 98%

See 1 more Smart Citation

Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

Say

Doğaç

Vovk

et al. 2014

Applied Catalysis B: Environmental

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“…Combined with the attribution of arc 3 to TPB-related proceeses, a possible explanation of the bend could be a change in the adsorbed NO x -species with increasing temperature. In-situ DRIFT measurements of NO adsorption on a model NO x -storage catalyst and on La 2 O 3 showed a change in the adsorbed NO x -species during temperature increase from 300 °C to 500 °C (39,40). This makes it likely a similar change will be observed when NO x is adsorbed on LSM15-CGO10 electrodes, and a change in the adsorbed NO x species would likely affect processes related to the TPB process like surface diffusion and dissociative adsorption, thereby causing the observed bend on the Arrhenious curved for arc 3.…”

Section: Eis Results -Identification Of Processesmentioning

confidence: 99%

Improvement of LSM15-CGO10 Electrodes for Electrochemical Removal of NOx by KNO3 and MnOx Impregnation

Traulsen¹

2011

J. Electrochem. Soc.

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LSM15-CGO10 (La0.85Sr0.15MnO3-Ce0.90Gd0.1O1.95) electrodes were impregnated with either KNO3 or MnOx, and the effect of the impregnations on the activity in NO containing atmospheres was investigated by electrochemical impedance spectroscopy and cyclic voltammetry. The electrodes were tested in 1000 ppm NO, 10% O2 and 1000 ppm NO + 10% O2 in the temperature range 300–500°C and the electrodes were investigated by scanning electron microscopy before and after testing. At 400–450°C a NOx-storage process was observed on the KNO3-impregnated electrodes, this process appeared to be dependent on preceding catalytically formation of NO2. Despite a marked difference in the microstructure of the impregnated KNO3 and MnOx, both impregnations caused a significant reduction in the polarization resistance of the electrodes, due to a general decrease in resistance of all the identified electrode processes. The effect of the impregnation was strongest at low temperatures, likely because the microstructure of the impregnated compounds changed at higher temperatures. Scanning electron microscopy images revealed a significant change in the microstructure of the impregnated samples after the test.

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“…Though the dynamic behavior of NO x on the catalyst surface is less interesting for industrial application, it is important to better understand the surface chemistry associated with the catalytic reaction [12] . Hence, the micro behavior of NO x on BaAl 2 O 4 was firstly investigated and subsequently, the reaction of adsorbed NO x with soot was studied.…”

Section: Adsorption Of No X On Baal 2 Omentioning

confidence: 99%