Researcher:
Koçer, Tolga

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Tolga

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Koçer

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Koçer, Tolga

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2021 - 20222

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Researcher Of Publications: search.filters.isAuthorOfPublication.57d37b5c-bb36-4f67-b6d3-78dc4ae3f49b

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    Graphene aerogel-supported ruthenium nanoparticles for COx-free hydrogen production from ammonia
    (Elsevier, 2021) N/A; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemistry; Department of Chemistry; Koçer, Tolga; Öztulum, Samira Fatma Kurtoğlu; Uzun, Alper; Ünal, Uğur; Öztuna, Feriha Eylül Saraç; Researcher; PhD Student; Faculty Member; Faculty Member; Researcher; Department of Chemical and Biological Engineering; Department of Chemistry; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; Graduate School of Sciences and Engineering; College of Engineering; College of Sciences; College of Sciences; N/A; 384798; 59917; 42079; N/A
    Ruthenium was highly dispersed on graphene aerogel (GA) at high loadings to achieve high performance in COx-free hydrogen production from ammonia. Catalytic performance measurements on ammonia decomposition showed that the GA-supported catalyst with a Ru loading of 13.6 wt% provides an ammonia conversion of 71.5 % at a space-velocity of 30,000 ml NH3 g(cat)(-1)h(-1) and at 450 degrees C, corresponding to a hydrogen production rate of 21.9 mmol H-2 g(cat)(-1)min(-1). The addition of K increased the ammonia conversion to a record high value of 97.6 % under identical conditions, reaching a hydrogen generation rate of 30.0 mmol H-2 g(cat)(-1) min(-1), demonstrated to be stable for at least 80 h. A comparison of the turnover frequencies of catalysts indicated that this increase in performance upon the addition of K originated from an increase in the number of the active Ru sites and the corresponding electron density available for reaction.
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    Effect of nickel precursor on the catalytic performance of graphene aerogel-supported nickel nanoparticles for the production of cox-free hydrogen by ammonia decomposition
    (Wiley-V C H Verlag Gmbh, 2022) N/A; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemistry; Department of Chemistry; Koçer, Tolga; Öztulum, Samira Fatma Kurtoğlu; Uzun, Alper; Ünal, Uğur; Öztuna, Feriha Eylül Saraç; Researcher; PhD Student; Faculty Member; Faculty Member; Researcher; Department of Chemical and Biological Engineering; Department of Chemistry; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; Graduate School of Sciences and Engineering; College of Engineering; College of Sciences; College of Sciences; N/A; 384798; 59917; 42079; N/A
    Graphene aerogel (GA), a promising porous material with high specific surface area and electrical conductivity, is utilized to disperse nickel nanoparticles to reach high catalytic activity in COx-free hydrogen production from ammonia. Ni(NO3)(2)center dot 6H(2)O and Ni (II) acetylacetonate (Ni(acac)(2)) were considered as metal precursors and the pH of the impregnation solution was varied to investigate the effects on the catalytic properties of the GA-supported nickel catalysts. Data showed that the best dispersion and homogeneity, as well as the catalytic performance, is achieved with Ni(acac)(2). An average Ni nanoparticle size of 13.6 +/- 4.3 nm was obtained on the GA-supported catalyst prepared by using Ni(acac)(2) dissolved in an impregnation solution with a pH of 10.2. This catalyst with a Ni loading of 11.1 wt% provided an ammonia conversion of 70.2% at a space velocity of 30 000 mL NH3 g(cat)(-1) h(-1) and 600 degrees C corresponding to a hydrogen production rate of 21.5 mmol H-2 g(cat)(-1) min(-1). Data illustrated that the difference between the point of zero charge of the support and the pH of the impregnation solution set by the type of the Ni precursor is a major parameter controlling the metal dispersion and the consequent catalytic activity.