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Nondeactivating nanosized ionic catalysts for water-gas shift reaction / Sudhanshu Sharma in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6535–6543 Titre : Nondeactivating nanosized ionic catalysts for water-gas shift reaction Type de document : texte imprimé Auteurs : Sudhanshu Sharma, Auteur ; Parag A. Deshpande, Auteur ; M. S. Hegde, Auteur Année de publication : 2009 Article en page(s) : pp. 6535–6543 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water-gas  shift  reaction  Nanosized  catalysts  X-ray  diffraction  X-ray  photoelectron  spectroscopy Résumé : The water−gas shift reaction (WGS) is an important reaction to produce hydrogen. In this study, we have synthesized nanosized catalysts where Pt ion is substituted in the +2 state in TiO2, CeO2, and Ce1−xTixO2−δ. These catalysts have been characterized by X-ray diffraction and X-ray photoelectron spectroscopy (XPS), and it has been shown that Pt2+ in these reducible oxides result in solid solutions like Ti0.99Pt0.01O2−δ, Ce0.83Ti0.15Pt0.02O2−δ, and Ce0.98Pt0.02O2−δ. These catalysts were tested for the water gas shift reaction both in the presence and absence of hydrogen. It was shown that Ti0.99Pt0.01O2−δ exhibited higher catalytic activity than Ce0.83Ti0.15Pt0.02O2−δ and Ce0.98Pt0.02O2−δ. Further, experiments were conducted to determine the deactivation of these catalysts. There was no sintering of Pt and no carbonate formation; therefore, the catalyst did not deactivate even after prolonged reaction. There was no carbonate formation because of the highly acidic nature of Ti4+ ions in the catalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900335k [article] Nondeactivating nanosized ionic catalysts for water-gas shift reaction [texte imprimé] / Sudhanshu Sharma, Auteur ; Parag A. Deshpande, Auteur ; M. S. Hegde, Auteur . - 2009 . - pp. 6535–6543. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6535–6543 Mots-clés : Water-gas  shift  reaction  Nanosized  catalysts  X-ray  diffraction  X-ray  photoelectron  spectroscopy Résumé : The water−gas shift reaction (WGS) is an important reaction to produce hydrogen. In this study, we have synthesized nanosized catalysts where Pt ion is substituted in the +2 state in TiO2, CeO2, and Ce1−xTixO2−δ. These catalysts have been characterized by X-ray diffraction and X-ray photoelectron spectroscopy (XPS), and it has been shown that Pt2+ in these reducible oxides result in solid solutions like Ti0.99Pt0.01O2−δ, Ce0.83Ti0.15Pt0.02O2−δ, and Ce0.98Pt0.02O2−δ. These catalysts were tested for the water gas shift reaction both in the presence and absence of hydrogen. It was shown that Ti0.99Pt0.01O2−δ exhibited higher catalytic activity than Ce0.83Ti0.15Pt0.02O2−δ and Ce0.98Pt0.02O2−δ. Further, experiments were conducted to determine the deactivation of these catalysts. There was no sintering of Pt and no carbonate formation; therefore, the catalyst did not deactivate even after prolonged reaction. There was no carbonate formation because of the highly acidic nature of Ti4+ ions in the catalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900335k

Photocatalytic activity of combustion synthesized ZrO2 and ZrO2 – TiO2 mixed oxides / Sneha Polisetti in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12915-12924 Titre : Photocatalytic activity of combustion synthesized ZrO2 and ZrO2 – TiO2 mixed oxides Type de document : texte imprimé Auteurs : Sneha Polisetti, Auteur ; Parag A. Deshpande, Auteur ; Giridhar Madras, Auteur Année de publication : 2012 Article en page(s) : pp. 12915-12924 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Titanium  oxide  Combustion  Photocatalysis Résumé : Tetragonal ZrO2, synthesized by solution combustion technique, was found to be photocatalytically active for the degradation of anionic dyes. The compound was characterized by FT-Raman spectroscopy, X-ray photoelectron spectroscopy, FT-infrared spectroscopy, UV―vis spectroscopy, BET surface area analysis, and zero point charge pH measurement. A high concentration of surface hydroxyl groups was observed over the catalyst, as confirmed by XPS and FTIR. The photocatalytic degradation of orange G, amido black, remazol brilliant blue R, and alizarin cyanine green (ACG) was carried out with this material. The effect of pH, inorganic salts, and H2O2 on the activity of the catalyst was also studied, and it was found that the catalyst maintained its activity at a wide range of pH and in the presence of inorganic salts. Having established that ZrO2 was photocatalytically active, mixed oxide catalysts of TiO2―ZrO2 were also tested for the photocatalytic degradation of ACG, and the 50% ZrO2―TiO2 mixed oxides showed activity that was comparable to the activity of TiO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267449 [article] Photocatalytic activity of combustion synthesized ZrO2 and ZrO2 – TiO2 mixed oxides [texte imprimé] / Sneha Polisetti, Auteur ; Parag A. Deshpande, Auteur ; Giridhar Madras, Auteur . - 2012 . - pp. 12915-12924. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12915-12924 Mots-clés : Titanium  oxide  Combustion  Photocatalysis Résumé : Tetragonal ZrO2, synthesized by solution combustion technique, was found to be photocatalytically active for the degradation of anionic dyes. The compound was characterized by FT-Raman spectroscopy, X-ray photoelectron spectroscopy, FT-infrared spectroscopy, UV―vis spectroscopy, BET surface area analysis, and zero point charge pH measurement. A high concentration of surface hydroxyl groups was observed over the catalyst, as confirmed by XPS and FTIR. The photocatalytic degradation of orange G, amido black, remazol brilliant blue R, and alizarin cyanine green (ACG) was carried out with this material. The effect of pH, inorganic salts, and H2O2 on the activity of the catalyst was also studied, and it was found that the catalyst maintained its activity at a wide range of pH and in the presence of inorganic salts. Having established that ZrO2 was photocatalytically active, mixed oxide catalysts of TiO2―ZrO2 were also tested for the photocatalytic degradation of ACG, and the 50% ZrO2―TiO2 mixed oxides showed activity that was comparable to the activity of TiO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267449

Selective catalytic reduction of NOx / Sounak Roy in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9240–9247 Titre : Selective catalytic reduction of NOx : mechanistic perspectives on the role of base metal and noble metal ion substitution Type de document : texte imprimé Auteurs : Sounak Roy, Auteur ; A. Marimuthu, Auteur ; Parag A. Deshpande, Auteur Année de publication : 2009 Article en page(s) : p. 9240–9247 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : NOx  Catalytic  Reduction  Noble  Metal  Ion  Substitution Résumé : Selective catalytic reduction (SCR) of NO by NH3 in presence of excess oxygen is an industrially and environmentally important reaction. Determining a suitable catalyst substituted with noble metals or base metal ions with a suitable reaction mechanism is important. In this study, ionically substituted Mn and Pd in TiO2 catalysts were synthesized by the solution combustion technique and examined for SCR activity. A seven-step reaction mechanism was proposed to incorporate the role of NH3 oxidation in the SCR reaction that shows minima in the NO concentration profile. Both modeling and experimental results show that the reduction of NO in SCR condition follows the order Ti0.9Mn0.1O2-δ > Ti0.89Mn0.1Pd0.01O2-δ > Ti0.99Pd0.01O2-δ. However, the hydrogen uptake study showed that the noble metal ion (Pd2+) substituted TiO2 has better reducibility than the base metal ion (Mn3+) substituted TiO2. The rate of ammonia oxidation by different catalysts followed the reverse order such as that of NO reduction. This clearly indicates that catalysts with higher reducibility and that which exhibit higher rates of ammonia oxidation have poor SCR activity. Thus, the base metal ion substitution is better than noble metal ion substitution for SCR. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010879#afn2 [article] Selective catalytic reduction of NOx : mechanistic perspectives on the role of base metal and noble metal ion substitution [texte imprimé] / Sounak Roy, Auteur ; A. Marimuthu, Auteur ; Parag A. Deshpande, Auteur . - 2009 . - p. 9240–9247. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9240–9247 Mots-clés : NOx  Catalytic  Reduction  Noble  Metal  Ion  Substitution Résumé : Selective catalytic reduction (SCR) of NO by NH3 in presence of excess oxygen is an industrially and environmentally important reaction. Determining a suitable catalyst substituted with noble metals or base metal ions with a suitable reaction mechanism is important. In this study, ionically substituted Mn and Pd in TiO2 catalysts were synthesized by the solution combustion technique and examined for SCR activity. A seven-step reaction mechanism was proposed to incorporate the role of NH3 oxidation in the SCR reaction that shows minima in the NO concentration profile. Both modeling and experimental results show that the reduction of NO in SCR condition follows the order Ti0.9Mn0.1O2-δ > Ti0.89Mn0.1Pd0.01O2-δ > Ti0.99Pd0.01O2-δ. However, the hydrogen uptake study showed that the noble metal ion (Pd2+) substituted TiO2 has better reducibility than the base metal ion (Mn3+) substituted TiO2. The rate of ammonia oxidation by different catalysts followed the reverse order such as that of NO reduction. This clearly indicates that catalysts with higher reducibility and that which exhibit higher rates of ammonia oxidation have poor SCR activity. Thus, the base metal ion substitution is better than noble metal ion substitution for SCR. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010879#afn2