Synthesis of High Purity Carbon Nano Fibers and Hydrogen from Propane Decomposition

Hussain, S.Tajammul,Gul, Sheraz,Mazhar, M.,Larachi, Faical Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.2

High purity carbon nano fibers/tubes (CNF/Ts) which contain 97% pure graphitic carbon are prepared by a new catalytic method. These carbon nano fibers/tubes are ready to use without any further purification. The striking feature of this method is the production of carbon nano fibers/tubes of narrow distribution range. The developed catalytic method also produces pure hydrogen. An additional advantage of this catalytic method is that catalyst can be reused without reactivation. Ni:Cu catalyst system is embodied into SCHOTT-DURAN filter disc of large pore size (40-100 mm). Due to the production of hydrogen in the reaction catalyst stability is enhanced and deactivation process is considerably slowed down.

Production of Hydrogen and Carbon Nanotubes from Catalytic Decomposition of Methane over Ni:Cu/Alumina Modified Supported Catalysts

Hussain, Tajammul,Mazhar, Mohammed,Iqbal, Sarwat,Gul, Sheraz,Hussain, Muzammil,Larachi, Faical Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.7

Hydrogen gas and carbon nanotubes along with nanocarbon were produced from commercial natural gas using fixed bed catalyst reactor system. The maximum amount of carbon (491 g/g of catalyst) formation was achieved on 25% Ni, 3% Cu supported catalyst without formation of CO/CO2. Pure carbon nanotubes with length of 308 nm having balloon and horn type shapes were also formed at 673 K. Three sets of catalysts were prepared by varying the concentration of Ni in the first set, Cu concentration in the second set and doping with K in the third set to investigate the effect on stabilization of the catalyst and production of carbon nanotubes and hydrogen by copper and potassium doping. Particle size analysis revealed that most of the catalyst particles are in the range of 20-35 nm. All the catalysts were characterized using powder XRD, SEM/EDX, TPR, CHN, BET and CO-chemisorption. These studies indicate that surface geometry is modified electronically with the formation of different Ni, Cu and K phases, consequently, increasing the surface reactivity of the catalyst and in turn the Carbon nanotubes/H2 production. The addition of Cu and K enhances the catalyst dispersion with the increase in Ni loadings and maximum dispersion is achieved on 25% Ni: 3% Cu/Al catalyst. Clearly, the effect of particle size coupled with specific surface geometry on the production of hydrogen gas and carbon nanotubes prevails. Addition of K increases the catalyst stability with decrease in carbon formation, due to its interaction with Cu and Ni, masking Ni and Ni:Cu active sites.

Synthesis of High Purity Carbon Nano Fibers and Hydrogen from Propane Decomposition

S. Tajammul Hussain*,Sheraz Gul,M. Mazhar,Faical Larachi 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.2

High purity carbon nano fibers/tubes (CNF/Ts) which contain 97% pure graphitic carbon are prepared by a new catalytic method. These carbon nano fibers/tubes are ready to use without any further purification. The striking feature of this method is the production of carbon nano fibers/tubes of narrow distribution range. The developed catalytic method also produces pure hydrogen. An additional advantage of this catalytic method is that catalyst can be reused without reactivation. Ni:Cu catalyst system is embodied into SCHOTT-DURAN filter disc of large pore size (40-100 mm). Due to the production of hydrogen in the reaction catalyst stability is enhanced and deactivation process is considerably slowed down.

Combined FTIR and Temperature Programmed Fischer-Tropsch Synthesis over Ru/SiO2 and Ru-Ag/SiO2 Supported Catalysts

Syed T. Hussain*,M. Arif Nadeem,M. Mazhar,Faical Larachi 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.4

Combined temperature programmed reaction (TPR) and infrared (IR) spectroscopic studies for Fischer-Tropsch reaction have been performed over Ru/SiO2 and Ru-Ag/SiO2 supported catalysts. Reaction of linearly absorbed CO with hydrogen starts at 375 K over Ru/SiO2 catalyst and reaches maximum at 420 K accompanied with an intensity decrease of linear CO absorption. The reaction with bridged absorbed CO peaks around 510-535 K. Addition of Ag yields mixed Ru-Ag bimetallic sites while it suppresses the formation of bridged bonded CO. Formation of methane on this modified surface occurs at 390 K and reaches maximum at 444 K. Suppression of hydrogen on the Ag-doped surface also occurs resulting in the formation of unsaturated hydrocarbons and of CHx intermediates not observed with Ru/SiO2 catalyst. Such intermediates are believed to be the building blocks of higher hydrocarbons during the Fischer-Tropsch synthesis. Linearly absorbed CO is found to be more reactive as compared to bridged CO. The Ag-modified surface also produces CO2 and carbon. On this surface, hydrogenation of CO begins at 390 K and reaches maximum at 494 K. The high temperature for hydrogenation of absorbed CO and C over Ru-Ag/SiO2 catalyst as compared to Ru/SiO2 catalyst is due to the formation of Ru-Ag bimetallic surfaces impeding hydrogen adsorption.

Combined FTIR and Temperature Programmed Fischer-Tropsch Synthesis over Ru/SiO₂ and Ru-Ag/SiO₂ Supported Catalysts

Hussain, Syed T.,Nadeem, M. Arif,Mazhar, M.,Larachi, Faical Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.4

Combined temperature programmed reaction (TPR) and infrared (IR) spectroscopic studies for Fischer- Tropsch reaction have been performed over Ru/SiO2 and Ru-Ag/SiO2 supported catalysts. Reaction of linearly absorbed CO with hydrogen starts at 375 K over Ru/SiO2 catalyst and reaches maximum at 420 K accompanied with an intensity decrease of linear CO absorption. The reaction with bridged absorbed CO peaks around 510-535 K. Addition of Ag yields mixed Ru-Ag bimetallic sites while it suppresses the formation of bridged bonded CO. Formation of methane on this modified surface occurs at 390 K and reaches maximum at 444 K. Suppression of hydrogen on the Ag-doped surface also occurs resulting in the formation of unsaturated hydrocarbons and of CHx intermediates not observed with Ru/SiO2 catalyst. Such intermediates are believed to be the building blocks of higher hydrocarbons during the Fischer-Tropsch synthesis. Linearly absorbed CO is found to be more reactive as compared to bridged CO. The Ag-modified surface also produces CO2 and carbon. On this surface, hydrogenation of CO begins at 390 K and reaches maximum at 494 K. The high temperature for hydrogenation of absorbed CO and C over Ru-Ag/SiO2 catalyst as compared to Ru/SiO2 catalyst is due to the formation of Ru-Ag bimetallic surfaces impeding hydrogen adsorption.

Production of hydrogen and Carbon Nanotubes from atalytic Decomposition of Methane over Ni:Cu/Alumina Modified Supported catalysts

Tajammul Hussain,Mohammed Mazhar,Sarwat Iqbal,Sheraz Gul,Muzammil Hussain,Faical Larachi 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.7

Hydrogen gas and carbon nanotubes along with nanocarbon were produced from commercial natural gas using fixed bed catalyst reactor system. The maximum amount of carbon(491 g/g of catalyst) formation was achieved on 25% Ni, 3% Cu supported catalyst without formation of CO/CO2. Pure carbon nanotubes with length of 308 nm having ballon and horn type shapes were also formed at 673K. Three sets of catalysts were prepared by varying the concentration of Ni in the first set, Cu concentration in the second set and doping with K in the thired set to investigate the effect on stabilization of the catalyst and production of carbon nanotubes and hydrogen by coper and potassium doping. Particle size analysis revealed that most of the ctalyst particled are in the range of 20-35 nm. All the catalysts were characterized using powder XRD, SEM/EDX, TPR, CHN, BET and CO-chemisorption. These studies indicate that surface geometry is modified electronically with the formation of different Ni, Cu and K phases, consequently, increasing the surface reactivity of the catalyst and in turm the Carbon nanotubes/H2 production. The addition of Cu and k enhances the catalyst dispersion with the increase in Ni loadings and maximum dispersion is achieved on 25% Ni: 3% Cu/Al catalyst. Clearly, the effect of particle size couple with specific surface geometry o nthe production of hydrogen gas and carbon nanotubes prevails. Addition of K increases the catalyst stability with decrease in carbon formation, due to its interaction with Cu and Ni, masking Ni and Ni: Cu active sites.

Ionic liquids [EMIM][BF4], [EMIM][Otf] and [BMIM][Otf] as corrosion inhibitors for CO2 capture applications

Anissa Acidi,Azzedine Abbaci,Muhammad Hasib-ur-Rahman,Faiçal Larachi 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.6

We present the viability of using thermally stable, practically non-volatile ionic liquids as corrosion inhibitorsin aqueous monoethanolamine systems. Carbon steel 1020, which is widely used as a construction material in CO2capture plants, has been taken as a test material. Corrosion inhibition capabilities of typical room-temperature ionicliquids constituting imidazolium cation in concentration range ≤3% in CO2 capture applications were investigated. Electrochemical corrosion experiments using the potentiodynamic polarization technique for measuring corrosion currentwere carried out. Subsequent calculation of corrosion rate via Tafel fit was performed. The experimental findingssuggest that the corrosion rate is significantly dependent on the process parameters, such as the CO2 loading and thepresence of oxygen. In addition, the value of the corrosion rate is sensitive to the type of ionic liquid added. Moreover,the results show that ionic liquids possess the ability of suppressing severe operational problems of corrosion in typicalCO2 capture plants to a reasonable extent (≥50%).