Preparation of highly active catalysts for ultra-clean fuels

Koizumi, Naoto; Mochizuki, Takehisa; Yamada, Masahito

doi:10.1016/j.cattod.2008.03.020

Cited by 26 publications

(32 citation statements)

References 33 publications

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“…[1,2] Their catalytic performance is strongly affected by cobalt dispersion: higher metal dispersion supposes higher proportion of reduced metal in the catalyst and lower average nanoparticle size. This can be achieved by optimizing catalyst texture, [3] adding organic compounds, [4] [5] or promoters [6] during catalyst preparation, decomposing cobalt nitrate in a glow discharge [7] or by controlling the catalyst thermal activation. [8,9,10,11] In particular, de Jong et al prepared smaller Co 3 O 4 and Co 0 particles on SBA-15 silicas by activating the catalyst in a NO-containing atmosphere instead of air prior to the reduction.…”

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confidence: 99%

A Time‐Resolved In Situ Quick‐XAS Investigation of Thermal Activation of Fischer–Tropsch Silica‐Supported Cobalt Catalysts

Hong

Marceau

Khodakov

et al. 2012

Chemistry A European J

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confidence: 99%

A Time‐Resolved In Situ Quick‐XAS Investigation of Thermal Activation of Fischer–Tropsch Silica‐Supported Cobalt Catalysts

Hong

Marceau

Khodakov

et al. 2012

Chemistry A European J

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“…The molar ratio of the organic additives to Co 2? , Y, was unity since the maximum conversion for Co(5)-NTA(Y)/SiO 2 was attained at this ratio [26]. In the absence of ZrO x modification, the conversions increased in a following order:…”

Section: Combination Effects Of Organic Additive and Zro X Promotersmentioning

confidence: 90%

Enhancing the Fischer–Tropsch Synthesis Activity of Co-based Catalysts by Adding ZrO x to the SiO2 Support and Chelating Ligands to the Co-precursor

et al. 2011

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Co/ZrO x /SiO 2 catalysts with enhanced dispersion of Co 0 and turnover frequency were successfully prepared combining two different promotion effects, i.e., modifications of SiO 2 surface with ZrO x by liquid phase deposition and influencing coordination structure of Co species using chelating agents or glycols. The catalysts exhibited *6.3-fold higher CO conversion than Co/SiO 2 and those promoted by organic additives or ZrO x alone, indicating activity enhancement was induced by cooperation of these two promoters.

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“…The polarized nature of both transition metal complexes and inorganic oxides causes the adsorption of species due to electrostatic interaction between them. The result of this interaction is a strong metal-support interaction on a catalyst [32][33][34] .…”

Section: Strong Metal-support Interactionmentioning

confidence: 99%

“…The complex formed possibly shows resistance to sintering as it contains a bulky structure where metal ions are surrounded by ligands. Figure 2.1 compares the space-time yield (STY) of C 10 -C 20 hydrocarbons (equivalent to diesel fraction) over the different catalysts 34 , each containing 5 w% cobalt. The STY of C 10 -C 20 hydrocarbon is higher for the catalyst with chelating agents.…”

Section: Modification With a Chelating Agentmentioning

confidence: 99%

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Study of the Effect of Surface Modification and Sulfur Impurities in Syngas on the Fischer-Tropsch Performance of Cobalt Catalysts

Bambal¹

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The effect of surface modification of the silica support on the Fischer-Tropsch (FT) activity and the selectivity of cobalt catalyst were studied. The catalysts were characterized by N 2physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and hydrogen chemisorption. FT was carried out in a fixed-bed reactor at 230 °C, 20 bar and 9000 sccm/h/g cat , using syngas with H 2 /CO = 2.0. Surface modification with chelating agents (CAs), i.e., nitrilotriacetic acid (NTA) and ethylenediaminetetracetic acid (EDTA), results in a smaller crystallite size of cobalt oxides after the calcination. In addition, the CA-modified catalysts contain well-dispersed cobalt oxides and higher number of catalytic sites on the surface. The CO conversions and the hydrocarbon yields, i.e., gC/Kg cat /h, are notably higher for the CA-modified catalysts at different operating temperatures. The structure-activity relationships based on the findings confirm the advantage of CA modification of the support during catalyst synthesis. In the next step, catalysts were subjected to poisoning by 10 and 50 ppm sulfur in the syngas. At both the concentrations, the sulfur is noted to adsorb irreversibly on the surface and to cause permanent loss in the activity. In the presence of sulfur, the performance of both CA-modified catalysts is better compared to that of the base catalyst. The sulfur poison affects the hydrogenation and the chainpropagation ability of the catalysts, and shifts the product selectivity towards short-chain hydrocarbons with a higher percentages of olefins. Highly dispersed CA-modified catalysts have a longer life in the presence of sulfur poison. iii ACKNOWLEDGEMENTS I would like to gratefully acknowledge the Department of Chemical Engineering, West Virginia University for providing me this fantastic opportunity to pursue PhD in the department. I would like express my sincere gratitude and appreciation to the enthusiastic supervision of Dr. Dady Dadyburjor during this doctoral research work. With his enthusiasm, his inspiration, and his great efforts to explain things clearly and simply, he helped to make this work, a great experience for me. Throughout my research, he provided encouragement, sound advice, good teaching, good company, and lots of sensible ideas. The work would be impossible without the always involved Dr. Edwin Kugler. My sincere thanks Dr. Todd Gardner for giving the opportunity through this project to work at NETL. I would also like to acknowledge Dr. John Zondlo and Dr. John Penn, for their willingness to serve as a member of my examining committee. Beyond the educational and technical guidance, my deepest thanks must go to my mother Sandhya Bambal and father Suresh Bambal who made everything in my life possible. Their love, belief, and guidance will never go unappreciated. I am forever indebted to my brother Manish Bambal and sister-in-law Trupti Bambal for their understanding, endless patience and encouragement when it was most required throughout...

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Preparation of highly active catalysts for ultra-clean fuels

Cited by 26 publications

References 33 publications

A Time‐Resolved In Situ Quick‐XAS Investigation of Thermal Activation of Fischer–Tropsch Silica‐Supported Cobalt Catalysts

A Time‐Resolved In Situ Quick‐XAS Investigation of Thermal Activation of Fischer–Tropsch Silica‐Supported Cobalt Catalysts

Enhancing the Fischer–Tropsch Synthesis Activity of Co-based Catalysts by Adding ZrO x to the SiO2 Support and Chelating Ligands to the Co-precursor

Study of the Effect of Surface Modification and Sulfur Impurities in Syngas on the Fischer-Tropsch Performance of Cobalt Catalysts

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