Low temperature NH3 selective catalytic reduction of NOx over substituted MnCr2O4 spinel-oxide catalysts / Miguel A. Zamudio in Industrial & engineering chemistry research, Vol. 50 N° 11 (Juin 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6668–6672 Titre : Low temperature NH3 selective catalytic reduction of NOx over substituted MnCr2O4 spinel-oxide catalysts Type de document : texte imprimé Auteurs : Miguel A. Zamudio, Auteur ; Nunzio Russo, Auteur ; Debora Fino, Auteur Année de publication : 2011 Article en page(s) : pp 6668–6672 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalysts X-ray diffraction Résumé : The present work describes the development of Mn1–xMxCr2O4 (M = Mg, Ca; x = 0–0.1) substituted spinel catalysts prepared via gel combustion synthesis for the low-temperature selective catalytic reduction (SCR) of NOx with NH3. The catalysts have been characterized by means of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FESEM) and temperature programmed reduction (TPR) analyses, whereas their catalytic activity has been tested in a temperature programmed reaction (TPRe) apparatus over a temperature range of 100–200 °C (W/F = 0.072 g·s·cm–3) in the presence of oxygen. The catalytic activity of alkali earth-metal substituted Mn–Cr spinels is compared with that of the stoichiometric MnCr2O4 in order to assess the effect of the substitutions. All the spinel catalysts have shown both high NO conversion and high selectivity to N2. Mn0.95Ca0.05Cr2O4 has shown the best performance, reaching an NO conversion of 96% and a selectivity to N2 of 97% at 125 °C. All the catalysts were then deposited by means of a modified dip-coating procedure over cordierite honeycomb monoliths and tested in a lab-scale test rig. The monolith catalyzed with the Mn0.95Ca0.05Cr2O4 spinel showed the best performance, reaching an NO conversion of 87.4% at 200 °C, with a good selectivity to N2 (94.8%). When the catalyzed monoliths were also tested in the presence of 10 vol % of water vapor, an activity decrease was observed. The correlation between the reducibility of the B site, determined from TPR experiments, and the spinels' catalytic activity order is discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200227u [article] Low temperature NH3 selective catalytic reduction of NOx over substituted MnCr2O4 spinel-oxide catalysts [texte imprimé] / Miguel A. Zamudio, Auteur ; Nunzio Russo, Auteur ; Debora Fino, Auteur . - 2011 . - pp 6668–6672. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6668–6672 Mots-clés : Catalysts X-ray diffraction Résumé : The present work describes the development of Mn1–xMxCr2O4 (M = Mg, Ca; x = 0–0.1) substituted spinel catalysts prepared via gel combustion synthesis for the low-temperature selective catalytic reduction (SCR) of NOx with NH3. The catalysts have been characterized by means of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FESEM) and temperature programmed reduction (TPR) analyses, whereas their catalytic activity has been tested in a temperature programmed reaction (TPRe) apparatus over a temperature range of 100–200 °C (W/F = 0.072 g·s·cm–3) in the presence of oxygen. The catalytic activity of alkali earth-metal substituted Mn–Cr spinels is compared with that of the stoichiometric MnCr2O4 in order to assess the effect of the substitutions. All the spinel catalysts have shown both high NO conversion and high selectivity to N2. Mn0.95Ca0.05Cr2O4 has shown the best performance, reaching an NO conversion of 96% and a selectivity to N2 of 97% at 125 °C. All the catalysts were then deposited by means of a modified dip-coating procedure over cordierite honeycomb monoliths and tested in a lab-scale test rig. The monolith catalyzed with the Mn0.95Ca0.05Cr2O4 spinel showed the best performance, reaching an NO conversion of 87.4% at 200 °C, with a good selectivity to N2 (94.8%). When the catalyzed monoliths were also tested in the presence of 10 vol % of water vapor, an activity decrease was observed. The correlation between the reducibility of the B site, determined from TPR experiments, and the spinels' catalytic activity order is discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200227u

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