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Alkali-promoted trimetallic Co−Rh−Mo sulfide catalysts for higher alcohols synthesis from synthesis gas: comparison of MWCNT and activated carbon supports / Venkateswara Rao Surisetty in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6956–6963 Titre : Alkali-promoted trimetallic Co−Rh−Mo sulfide catalysts for higher alcohols synthesis from synthesis gas: comparison of MWCNT and activated carbon supports Type de document : texte imprimé Auteurs : Venkateswara Rao Surisetty, Auteur ; Ajay Kumar Dalai, Auteur ; Janusz Kozinski, Auteur Année de publication : 2010 Article en page(s) : pp 6956–6963 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalysts  Trimetallic  Gas. Résumé : Multiwalled carbon nanotubes (MWCNTs) and activated carbon were used as supports for the Co (4.5 and 6 wt %) promoted K (9 wt %) modified Rh−Mo catalysts (1.5 wt % Rh and 15 wt % Mo). The catalysts were extensively characterized in both oxide and sulfide phases. A drastic fall in surface area over the activated carbon-supported catalysts was observed after impregnating with metal species. Diffraction peaks were observed in the X-ray diffraction (XRD) patterns of the sulfided alkali-modified trimetallic catalysts, due to the characteristic reflections of the K−Mo−S mixed phase. H2-temperature programmed reduction (TPR) profiles showed that the reduction behavior of metal species was improved with the addition of Co. The activated carbon-supported trimetallic catalysts showed less activity and selectivity compared to the MWCNT-supported catalyst, and metal dispersions were higher on the MWCNT-supported catalysts. The MWCNT-supported, alkali-promoted trimetallic catalyst with 4.5 wt % Co showed the highest total alcohols yield of 0.244 g/(g cat h), ethanol selectivity of 20.1%, and higher alcohols selectivity of 31.4% at 320 °C and 8.28 MPa using a gas hourly space velocity (GHSV) of 3.6 m3 (STP)/(kg catalyst h). A maximum total alcohol yield of 0.261 g/(g cat h) and a selectivity of 42.9% were obtained on the 4.5 wt % Co−Rh−Mo−K/MWCNT catalyst, at a temperature of 330 °C. The total alcohol yield increased from 0.163 to 0.256 g/(g cat h) with increased pressure from 5.52 MPa (800 psig) to 9.65 MPa (1400 psig) over the 4.5 wt % Co−Rh−Mo−K/MWCNT catalyst. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100427j [article] Alkali-promoted trimetallic Co−Rh−Mo sulfide catalysts for higher alcohols synthesis from synthesis gas: comparison of MWCNT and activated carbon supports [texte imprimé] / Venkateswara Rao Surisetty, Auteur ; Ajay Kumar Dalai, Auteur ; Janusz Kozinski, Auteur . - 2010 . - pp 6956–6963. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6956–6963 Mots-clés : Catalysts  Trimetallic  Gas. Résumé : Multiwalled carbon nanotubes (MWCNTs) and activated carbon were used as supports for the Co (4.5 and 6 wt %) promoted K (9 wt %) modified Rh−Mo catalysts (1.5 wt % Rh and 15 wt % Mo). The catalysts were extensively characterized in both oxide and sulfide phases. A drastic fall in surface area over the activated carbon-supported catalysts was observed after impregnating with metal species. Diffraction peaks were observed in the X-ray diffraction (XRD) patterns of the sulfided alkali-modified trimetallic catalysts, due to the characteristic reflections of the K−Mo−S mixed phase. H2-temperature programmed reduction (TPR) profiles showed that the reduction behavior of metal species was improved with the addition of Co. The activated carbon-supported trimetallic catalysts showed less activity and selectivity compared to the MWCNT-supported catalyst, and metal dispersions were higher on the MWCNT-supported catalysts. The MWCNT-supported, alkali-promoted trimetallic catalyst with 4.5 wt % Co showed the highest total alcohols yield of 0.244 g/(g cat h), ethanol selectivity of 20.1%, and higher alcohols selectivity of 31.4% at 320 °C and 8.28 MPa using a gas hourly space velocity (GHSV) of 3.6 m3 (STP)/(kg catalyst h). A maximum total alcohol yield of 0.261 g/(g cat h) and a selectivity of 42.9% were obtained on the 4.5 wt % Co−Rh−Mo−K/MWCNT catalyst, at a temperature of 330 °C. The total alcohol yield increased from 0.163 to 0.256 g/(g cat h) with increased pressure from 5.52 MPa (800 psig) to 9.65 MPa (1400 psig) over the 4.5 wt % Co−Rh−Mo−K/MWCNT catalyst. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100427j

Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst / Jianguo Zhang in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 677–684 Titre : Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst Type de document : texte imprimé Auteurs : Jianguo Zhang, Auteur ; Hui Wang, Auteur ; Ajay Kumar Dalai, Auteur Année de publication : 2009 Article en page(s) : p. 677–684 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Bimetallic  Catalyst Résumé : The kinetics of CO2 reforming with CH4 over a Ni−Co/Al−Mg−O bimetallic catalyst was investigated in a fixed bed reactor at a temperature range of 650−750 °C and the partial pressures of CO2 and CH4 ranging from 30 to 190 kPa. Owing to the simultaneous occurrence of the CO2 reforming reaction and the reverse water−gas shift reaction (RWGS) in the system, the apparent activation energies with respect to reactant consumption and product formation were found different and they are 69.4 and 25.9 kJ/mol for CH4 and CO2 consumption and 85.1 and 61.8 kJ/mol for H2 and CO formation, respectively. It was also found that the reforming rate in terms of CH4 consumption was less sensitive to CO2 partial pressures but had stronger dependence on CH4 partial pressures. At a constant CH4 partial pressure, the increase in CO2 partial pressure did not cause significant change in the reforming rate, whereas at a constant CO2 partial pressure the reforming rate increased with the increase in CH4 partial pressure. The increase in extra CO2 at a constant CH4 pressure led to decreases in hydrogen (H2) formation but increase in carbon monoxide (CO) formation due to the simultaneous occurrence of the reverse water-gas shift reaction. A Langmuir−Hinshelwood (L–H) model was also developed assuming that the dissociation of CH4 and the reaction between the carbon species and the activated carbon dioxide are the rate determining steps over the Ni–Co/Al–Mg–O. It satisfactorily fits the experimental data as well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801078p [article] Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst [texte imprimé] / Jianguo Zhang, Auteur ; Hui Wang, Auteur ; Ajay Kumar Dalai, Auteur . - 2009 . - p. 677–684. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 677–684 Mots-clés : Bimetallic  Catalyst Résumé : The kinetics of CO2 reforming with CH4 over a Ni−Co/Al−Mg−O bimetallic catalyst was investigated in a fixed bed reactor at a temperature range of 650−750 °C and the partial pressures of CO2 and CH4 ranging from 30 to 190 kPa. Owing to the simultaneous occurrence of the CO2 reforming reaction and the reverse water−gas shift reaction (RWGS) in the system, the apparent activation energies with respect to reactant consumption and product formation were found different and they are 69.4 and 25.9 kJ/mol for CH4 and CO2 consumption and 85.1 and 61.8 kJ/mol for H2 and CO formation, respectively. It was also found that the reforming rate in terms of CH4 consumption was less sensitive to CO2 partial pressures but had stronger dependence on CH4 partial pressures. At a constant CH4 partial pressure, the increase in CO2 partial pressure did not cause significant change in the reforming rate, whereas at a constant CO2 partial pressure the reforming rate increased with the increase in CH4 partial pressure. The increase in extra CO2 at a constant CH4 pressure led to decreases in hydrogen (H2) formation but increase in carbon monoxide (CO) formation due to the simultaneous occurrence of the reverse water-gas shift reaction. A Langmuir−Hinshelwood (L–H) model was also developed assuming that the dissociation of CH4 and the reaction between the carbon species and the activated carbon dioxide are the rate determining steps over the Ni–Co/Al–Mg–O. It satisfactorily fits the experimental data as well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801078p