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Au/CuOx-TiO2 catalysts for preferential oxidation of CO in hydrogen sStream / Palanivelu Sangeetha in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2096–2102 Titre : Au/CuOx-TiO2 catalysts for preferential oxidation of CO in hydrogen sStream Type de document : texte imprimé Auteurs : Palanivelu Sangeetha, Auteur ; Zhao, Bin, Auteur ; Chen, Yu-Wen, Auteur Année de publication : 2010 Article en page(s) : pp. 2096–2102 Note générale : Industrial Chemisty Langues : Anglais (eng) Mots-clés : Catalysts;  Au/CuOx-TiO2;  Preferential  Oxidation Résumé : A series of Au/CuOx−TiO2 catalysts with various Cu/Ti atomic ratios were prepared by deposition−precipitation method. The catalysts were characterized by inductively coupled plasma−mass spectrometry, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The preferential oxidation of CO in H2 stream (PROX) on these catalysts was carried out in a fixed bed microreactor with a gas mixture (CO:O2:H2:He = 1.33:1.33:65.33:32.01 by volume ratios) was fed with a space velocity of 30000 mL/(g·h). Au/CuOx−TiO2 with various Cu/Ti atomic ratios showed similar gold particle size (2.3−2.5 nm). The gold in the starting material was almost totally loaded on the CuOx−TiO2 support at pH = 7. Au/CuOx−TiO2 catalysts with gold content of 1 wt % and calcined at 180 °C had superior catalytic activity and selectivity for CO oxidation at temperature of 80 °C. Au/CuOx−TiO2 (Cu/Ti = 4.8/95.2) had a CO conversion of 100% at 80 °C, and CO selectivity reaches 68%. Gold particles were well dispersed and stable on the support. Even after PROX reaction at 80 °C for a long time, most of the particles still maintained at 2.4 nm. The CO conversion slightly decreased from 100% to 95%, and CO selectivity was nearly the same. Au/CuOx−TiO2 is a highly effective and thermally stable catalyst for PROX reaction compared with Au/TiO2 catalyst. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901233e [article] Au/CuOx-TiO2 catalysts for preferential oxidation of CO in hydrogen sStream [texte imprimé] / Palanivelu Sangeetha, Auteur ; Zhao, Bin, Auteur ; Chen, Yu-Wen, Auteur . - 2010 . - pp. 2096–2102. Industrial Chemisty Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2096–2102 Mots-clés : Catalysts;  Au/CuOx-TiO2;  Preferential  Oxidation Résumé : A series of Au/CuOx−TiO2 catalysts with various Cu/Ti atomic ratios were prepared by deposition−precipitation method. The catalysts were characterized by inductively coupled plasma−mass spectrometry, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The preferential oxidation of CO in H2 stream (PROX) on these catalysts was carried out in a fixed bed microreactor with a gas mixture (CO:O2:H2:He = 1.33:1.33:65.33:32.01 by volume ratios) was fed with a space velocity of 30000 mL/(g·h). Au/CuOx−TiO2 with various Cu/Ti atomic ratios showed similar gold particle size (2.3−2.5 nm). The gold in the starting material was almost totally loaded on the CuOx−TiO2 support at pH = 7. Au/CuOx−TiO2 catalysts with gold content of 1 wt % and calcined at 180 °C had superior catalytic activity and selectivity for CO oxidation at temperature of 80 °C. Au/CuOx−TiO2 (Cu/Ti = 4.8/95.2) had a CO conversion of 100% at 80 °C, and CO selectivity reaches 68%. Gold particles were well dispersed and stable on the support. Even after PROX reaction at 80 °C for a long time, most of the particles still maintained at 2.4 nm. The CO conversion slightly decreased from 100% to 95%, and CO selectivity was nearly the same. Au/CuOx−TiO2 is a highly effective and thermally stable catalyst for PROX reaction compared with Au/TiO2 catalyst. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901233e

Au/FeOx−TiO2 catalysts for the preferential oxidation of CO in a H2 stream / Yi-Fen Yang in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10402–10407 Titre : Au/FeOx−TiO2 catalysts for the preferential oxidation of CO in a H2 stream Type de document : texte imprimé Auteurs : Yi-Fen Yang, Auteur ; Palanivelu Sangeetha, Auteur ; Chen, Yu-Wen, Auteur Année de publication : 2010 Article en page(s) : pp. 10402–10407 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Au/FeOx−TiO2--Catalysts--Preferential--Oxidation--CO--H2--Stream Résumé : A series of gold catalysts supported on Fe2O3−TiO2 with various iron contents were prepared. A FeOx−TiO2 support was prepared via incipient-wetness impregnation with aqueous solution of Fe(NO3)3 on TiO2. A gold catalyst with a nominal loading of 1 wt % was prepared by deposition−precipitation at pH 7 and 65 °C. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performance of these catalysts were investigated by preferential oxidation of carbon monoxide in hydrogen stream (PROX). The reaction was conducted in a fixed-bed microreactor with a feed of CO:O2:H2:He = 1:1:49:49 (volume ratios). A limited amount of oxygen was used. Gold catalysts have been reported to be efficient catalysts for the PROX reaction to reduce CO concentration to <50 ppm. The Au/TiO2 catalyst had high CO and H2 oxidation activity. However, CO conversion decreases obviously when the temperature reaches above 80 °C, because of the competition of hydrogen oxidation on the catalysts. In this study, FeOx was added to Au/TiO2 to suppress H2 oxidation without sacrificing the activity for CO oxidation. Adding a suitable amount of Fe2O3 on Au/TiO2 could enhance CO conversion to a higher extent and suppress H2 oxidation. In the highly active gold-supported catalysts, the amorphous nature of Fe2O3, along with TiO2, not only enhanced electronic interaction but also stabilized the nanosized gold particles, thereby enhancing the catalytic activity of CO oxidation toward a higher extent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900806r [article] Au/FeOx−TiO2 catalysts for the preferential oxidation of CO in a H2 stream [texte imprimé] / Yi-Fen Yang, Auteur ; Palanivelu Sangeetha, Auteur ; Chen, Yu-Wen, Auteur . - 2010 . - pp. 10402–10407. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10402–10407 Mots-clés : Au/FeOx−TiO2--Catalysts--Preferential--Oxidation--CO--H2--Stream Résumé : A series of gold catalysts supported on Fe2O3−TiO2 with various iron contents were prepared. A FeOx−TiO2 support was prepared via incipient-wetness impregnation with aqueous solution of Fe(NO3)3 on TiO2. A gold catalyst with a nominal loading of 1 wt % was prepared by deposition−precipitation at pH 7 and 65 °C. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performance of these catalysts were investigated by preferential oxidation of carbon monoxide in hydrogen stream (PROX). The reaction was conducted in a fixed-bed microreactor with a feed of CO:O2:H2:He = 1:1:49:49 (volume ratios). A limited amount of oxygen was used. Gold catalysts have been reported to be efficient catalysts for the PROX reaction to reduce CO concentration to <50 ppm. The Au/TiO2 catalyst had high CO and H2 oxidation activity. However, CO conversion decreases obviously when the temperature reaches above 80 °C, because of the competition of hydrogen oxidation on the catalysts. In this study, FeOx was added to Au/TiO2 to suppress H2 oxidation without sacrificing the activity for CO oxidation. Adding a suitable amount of Fe2O3 on Au/TiO2 could enhance CO conversion to a higher extent and suppress H2 oxidation. In the highly active gold-supported catalysts, the amorphous nature of Fe2O3, along with TiO2, not only enhanced electronic interaction but also stabilized the nanosized gold particles, thereby enhancing the catalytic activity of CO oxidation toward a higher extent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900806r

Preferential oxidation of CO in H2 stream on Au/TiO2 catalysts / Palanivelu Sangeetha in Industrial & engineering chemistry research, Vol. 48 N° 12 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5666–5670 Titre : Preferential oxidation of CO in H2 stream on Au/TiO2 catalysts : effect of preparation method Type de document : texte imprimé Auteurs : Palanivelu Sangeetha, Auteur ; Li-Hsin Chang, Auteur ; Chen, Yu-Wen, Auteur Année de publication : 2009 Article en page(s) : pp. 5666–5670 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Au/TiO2  catalysts  Deposition-precipitation  methods  Inductively  coupled  plasma-mass  spectrometry  X-ray  diffraction  Transmission  electron  microscopy  X-ray  photoelectron  spectroscopy Résumé : A series of Au/TiO2 catalysts were prepared by either photodeposition or deposition−precipitation methods. The catalysts were characterized by inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of these catalysts was investigated by preferential oxidation of carbon monoxide in a hydrogen stream. A high gold dispersion and narrow size distribution was obtained for Au/TiO2 catalysts prepared by both photodeposition or deposition−precipitation methods. The photodeposition method facilitates the preparation of gold particles as small as 1.5 nm on the support, whereas in the deposition−precipitation method, the gold particles were found to be around 2−3 nm. The catalyst prepared by the photodeposition method showed higher CO conversion and CO selectivity than those prepared by the deposition−precipitation method. The selectivity of CO reacting with O2 decreased with increasing reaction temperature due to H2 competing with CO at high temperatures. Au/TiO2 catalysts prepared by the photodeposition method showed relatively higher CO selectivity below 65 °C when compared with the deposition−precipitation method. The differences in activity could be attributed to the difference in chemical state of gold particles and the particle size of gold. The catalyst prepared by photodeposition had a smaller particle size (1.5 nm). It had higher CO conversion at low temperature (<50 °C). However, the CO conversion and CO selectivity is low between 50 and 100 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900403s [article] Preferential oxidation of CO in H2 stream on Au/TiO2 catalysts : effect of preparation method [texte imprimé] / Palanivelu Sangeetha, Auteur ; Li-Hsin Chang, Auteur ; Chen, Yu-Wen, Auteur . - 2009 . - pp. 5666–5670. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5666–5670 Mots-clés : Au/TiO2  catalysts  Deposition-precipitation  methods  Inductively  coupled  plasma-mass  spectrometry  X-ray  diffraction  Transmission  electron  microscopy  X-ray  photoelectron  spectroscopy Résumé : A series of Au/TiO2 catalysts were prepared by either photodeposition or deposition−precipitation methods. The catalysts were characterized by inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of these catalysts was investigated by preferential oxidation of carbon monoxide in a hydrogen stream. A high gold dispersion and narrow size distribution was obtained for Au/TiO2 catalysts prepared by both photodeposition or deposition−precipitation methods. The photodeposition method facilitates the preparation of gold particles as small as 1.5 nm on the support, whereas in the deposition−precipitation method, the gold particles were found to be around 2−3 nm. The catalyst prepared by the photodeposition method showed higher CO conversion and CO selectivity than those prepared by the deposition−precipitation method. The selectivity of CO reacting with O2 decreased with increasing reaction temperature due to H2 competing with CO at high temperatures. Au/TiO2 catalysts prepared by the photodeposition method showed relatively higher CO selectivity below 65 °C when compared with the deposition−precipitation method. The differences in activity could be attributed to the difference in chemical state of gold particles and the particle size of gold. The catalyst prepared by photodeposition had a smaller particle size (1.5 nm). It had higher CO conversion at low temperature (<50 °C). However, the CO conversion and CO selectivity is low between 50 and 100 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900403s