Understanding the synergistic catalytic effect between La2O3 and CaO for the CH4 lean De-NOx reaction: Kinetic and mechanistic studies
| dc.contributor.author | Anastasiadou, T. | en |
| dc.contributor.author | Loukatzikou, L. A. | en |
| dc.contributor.author | Costa, C. N. | en |
| dc.contributor.author | Efstathiou, A. M. | en |
| dc.date.accessioned | 2015-11-24T16:51:54Z | |
| dc.date.available | 2015-11-24T16:51:54Z | |
| dc.identifier.issn | 1520-6106 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/9804 | |
| dc.rights | Default Licence | - |
| dc.subject | silica-supported platinum | en |
| dc.subject | nitric-oxide | en |
| dc.subject | selective reduction | en |
| dc.subject | n2o decomposition | en |
| dc.subject | calcium-oxide | en |
| dc.subject | earth-oxides | en |
| dc.subject | plus co | en |
| dc.subject | methane | en |
| dc.subject | adsorption | en |
| dc.subject | surface | en |
| dc.title | Understanding the synergistic catalytic effect between La2O3 and CaO for the CH4 lean De-NOx reaction: Kinetic and mechanistic studies | en |
| heal.abstract | Doping of La2O3 crystallites with Ca2+ ions significantly enhances the intrinsic rate of NO reduction by CH4 in the presence of 5% O-2 at 550 degrees C compared to pure La2O3 and CaO solids, while the opposite is true after doping of CaO with La3+ ions. It was found that the 5 wt % La2O3-95 wt % CaO system has one of the highest intrinsic site reactivities (TOF = 8.5 x 10(-3) s(-1)) reported at 550 degrees C for the NO/CH4/O-2 reaction among metal oxide surfaces. The doping process occurred after first dispersing La2O3 and CaO crystallites in deionized water heated to 60 degrees C for 90 min, while the dried material was then ground and heated slowly in air to 800 degrees C and kept at this temperature for 5 h. The doping process had the effect of creating surface oxygen vacant sites (F-type defects) in the oxide lattices the concentration of which is a function of the wt % La2O3 used in the mixed oxide system as revealed by photoluminescence and O-2 chernisorption studies. According to DRIFTS (NO)-N-15 transient isotopic experiments (SSITKA), oxygen vacant sites in Ca2+-doped La2O3 promote the formation of a more active chemisorbed NOx species (NO2-) that contributes to the enhancement of reaction rate as compared to pure lanthana, calcium oxide, and La3+-doped CaO. These results were supported by the kinetic orders of the reaction with respect to NO and O-2 obtained as a function of wt % La2O3 content in the mixed oxide system. Carbon dioxide (a reaction product) competes for the same oxygen vacant sites to form stable adsorbed carbonate-like species, thus lowering the reduction rate of NO. The dependence of the reaction TOF on the wt % La2O3 loading at 550 degrees C was found to follow the trend of the dependence of photoluminescence intensity on the wt % La2O3 content in the La2O3-CaO oxide system. | en |
| heal.access | campus | - |
| heal.fullTextAvailability | TRUE | - |
| heal.identifier.primary | Doi 10.1021/Jp0515582 | - |
| heal.identifier.secondary | <Go to ISI>://000230526800042 | - |
| heal.identifier.secondary | http://pubs.acs.org/doi/pdfplus/10.1021/jp0515582 | - |
| heal.journalName | Journal of Physical Chemistry B | en |
| heal.journalType | peer reviewed | - |
| heal.language | en | - |
| heal.publicationDate | 2005 | - |
| heal.publisher | American Chemical Society | en |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας | el |
| heal.type | journalArticle | - |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.type.en | Journal article | en |
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