Hydrogen generation of conventional fuels over mesoporous mixed oxide catalysts under time interrrupted reaction conditions

Can, Mukaddes
In this study, catalytic activity of the Co and/or Pb-SBA-15 mesoporous catalysts in methane partial oxidation reaction was investigated. By using sol-gel, incipient wetness impregnation and post grafting method, SBA-15 samples are incorporated with Co and/or Pb at different weight loadings to provide a controlled geometry in nanometer scale. The characterization of the synthesized samples was done by XRD, N2 adsorption isotherms, FTIR, TEM images, Raman and XPS analysis. In the present study also, gas phase methane partial oxidation modeling and the synthesizing of mesoporous SBA-15 silica with different pore sizes were investigated. For the samples prepared by sol-gel method, XRD analysis showedthat cobalt exists in the form of Co3O4and Pb exist in the form of PbO. BET surface areas of the Co loaded catalysts are in the range of 479.5-640.1 m2/g. However, in Pb loaded samples, higher metal loading decrease the surface area up to 4.63 m2/g. Considering the both Co and Pb containing bi-metallic samples, TEM and BET results revealed that the ordered hexagonal mesostructure was fully destroyed. The samples prepared by incipient wetness impregnation and post grafting method characterized by using BET, TEM, Raman and XPS analysis. According to the BET results all the samples show ordered mesostructure in agreement with TEM results for all Co and/or SBA-15 mesoporous samples. TEM results also revealed that, the Co(5%) Pb(5%)-SBA-15 catalyst prepared by incipient wetness impregnation method possess big cobalt and lead oxide crystallines on the mesoporous structure. Raman analysis results indicated that cobalt exist in Co3O4 form. According to XPS results all samples containing cobalt include Co3O4. The partial oxidation of methane was carried out in a fixed bed flow-type reactor in a temperature range of 50–850°C under atmospheric pressure.According to the reaction test results, the 0.5%Rh-Co-SBA15 catalyst shows the highest methane conversion (82%) and H2 selectivity. The non-precious metal show lower reactivities, addition of Pb to the Co-SBA-15 catalyst increases the catalytic activity and decrease the H2 production temperature.


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Previously being used as highly active catalyst in the hydrolysis of sodium borohydride, intrazeolite cobalt(0) nanoclusters were also employed as catalyst in the hydrolysis of ammonia-borane (H(3)NBH(3)). Intrazeolite cobalt(0) nanoclusters were found to be active catalyst in this hydrolysis reaction of ammonia-borane providing 5450 total turnovers at room temperature before deactivation. The results of the kinetic study shows that the catalytic hydrolysis of AB is first order with respect to the catalyst ...
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VARIŞLI, DİLEK; Korkusuz, Cansu; Doğu, Timur (2017-02-01)
Microwave-assisted ammonia decomposition reaction was investigated to produce COx free hydrogen, for fuel cell applications. Iron incorporated mesoporous carbon catalysts were prepared at different metal loadings, following an impregnation procedure. Mesoporous carbon acted as the catalyst support, as well as the microwave receptor. Complete conversion of ammonia was achieved at 450 degrees C over the catalyst having 7.7 wt% Fe, when the reaction was carried out in the microwave reactor system, using pure a...
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Guler, Melih; Doğu, Timur; VARIŞLI, DİLEK (2017-12-15)
Ammonia decomposition reaction to produce COx free hydrogen over molybdenum incorporated mesoporous carbon based catalysts was studied in a microwave heated reactor system. Mesoporous carbon is acting as the catalyst support as well as the microwave receptor in the reaction medium. While the highest conversion value was 49% in conventionally heated reaction system at 600 degrees C, total conversion value was achieved over the same catalyst at 400 degrees C in microwave heated system with a GHSV of 36,000 ml...
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Herein, we report the preparation and characterization of rhodium(0) nanoparticles supported on hydroxyapatite (Ca-10(OH)(2)(PO4)(6), HAP) and their catalytic use in the hydrolysis of hydrazine-borane, which attracts recent attention as promising hydrogen storage materials. Hydroxyapatite supported rhodium(0) nanoparticles were readily prepared by the hydrazine-borane reduction of rhodium(III)-exchanged hydroxyapatite in situ during the hydrolysis of hydrazine-borane at room temperature. Characterization of...
Combustion kinetics of oil shales by reaction cell experiments
Kök, Mustafa Verşan; Bagci, S. (Estonian Academy Publishers, 2008-01-01)
In this study, kinetics parameters of combustion reaction of Seyitomer and Beypazari oil shales were determined using Weijdema's model of reaction kinetics. The analysis of reaction kinetics experiments showed two different reaction regions at combustion of Beypazari oil shale sample. Only one reaction region was observed at combustion of Seyitomer oil shale. CO2/CO ratios increased gradually at low and medium temperatures and stabilized at high temperatures, especially after complete combustion. A decrease...
Citation Formats
M. Can, “Hydrogen generation of conventional fuels over mesoporous mixed oxide catalysts under time interrrupted reaction conditions,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.