Researcher:
Güneş, Hande

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PhD Student

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Hande

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Güneş

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Güneş, Hande
Akıncıtürk, Hande Güneş

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2020 - 20224

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Researcher Of Publications: search.filters.isAuthorOfPublication.6061c23d-1ad8-4731-bad6-9e33d8f14c96

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Now showing 1 - 4 of 4
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    PublicationOpen Access
    Preparation of Pt/Al2O3 and PtPd/Al2O3 catalysts by supercritical deposition and their performance for oxidation of nitric oxide and propene
    (Elsevier, 2020) Şanlı Yıldız, D.; Özener, B.; Hisar, G.; Rommel, S.; Aindow, M.; Department of Chemical and Biological Engineering; Güneş, Hande; Bozbağ, Selmi Erim; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 29633
    Pt/Al2O3 and bimetallic PtPd/Al2O3 catalysts were prepared via supercritical deposition method using supercritical carbon dioxide. The effects of Pt loading of Pt/Al2O3 and Pd addition to Pt/Al2O3 on particle size, particle size distribution (PSD) and activity for NO and C3H6 oxidation and C3H6-selective catalytic reduction (C3H6-SCR) were investigated. Pt/Al2O3 catalysts were prepared with Pt loadings of 0.6, 1.2 and 2.1 wt% and a bimetallic PtPd/Al2O3 catalyst was prepared with total metal loading of 1.4 wt% and Pt:Pd molar ratio of 1.3:1. A small fraction of the particles agglomerated after calcination at 550 °C. Around 98 % of the particles had an average particle size of ?1 nm. The rest of the particles were larger and average size of these larger particles was ?10 nm for monometallic catalysts and ?6.5 nm for PtPd/Al2O3. All catalysts were found to be active for NO and C3H6 oxidation and C3H6-SCR reactions. NO oxidation performance of 1.2 wt% Pt/Al2O3 catalyst was the highest. C3H6 oxidation activity increased with increasing metal content. Light-off temperature for C3H6 oxidation shifted to higher temperature in the presence of NO, suggesting competitive oxidation of C3H6 and NO. Concentration profiles indicated that C3H6-SCR started when C3H6 conversion by oxidation reached 50 %; C3H6 was consumed both by oxidation and C3H6-SCR at higher conversions.
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    PublicationOpen Access
    A promising catalyst for the dehydrogenation of perhydro-dibenzyltoluene: Pt/Al2O3 prepared by supercritical CO2 deposition
    (Multidisciplinary Digital Publishing Institute (MDPI), 2022) Modisha, Phillimon; Garidzirai, Rudaviro; Rommel, Sarshad; Uzunlar, Erdal; Aindow, Mark; Bessarabov, Dmitri; Department of Chemical and Biological Engineering; Bozbağ, Selmi Erim; Erkey, Can; Güneş, Hande; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); College of Engineering; N/A; 29633; N/A
    Pt/Al2O3 catalysts prepared via supercritical deposition (SCD), with supercritical CO2, wet impregnation (WI) methods and a selected benchmark catalyst, were evaluated for the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) at 300 degrees C in a batch reactor. After ten dehydrogenation runs, the average performance of the catalyst prepared using SCD was the highest compared to the benchmark and WI-prepared catalysts. The pre-treatment of the catalysts with the product (dibenzyltoluene) indicated that the deactivation observed is mainly due to the adsorbed H0-DBT blocking the active sites for the reactant (H18-DBT). Furthermore, the SCD method afforded a catalyst with a higher dispersion of smaller sized Pt particles, thus improving catalytic performance towards the dehydrogenation of H18-DBT. The particle diameters of the SCD- and WI-prepared catalysts varied in the ranges of 0.6-2.2 nm and 0.8-3.4 nm and had average particle sizes of 1.1 nm and 1.7 nm, respectively. Energy dispersive X-ray spectroscopy analysis of the catalysts after ten dehydrogenation runs revealed the presence of carbon. In this study, improved catalyst performance led to the production of more liquid-based by-products and carbon material compared to catalysts with low catalytic performance.
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    PublicationOpen Access
    Investigation of performances of commercial diesel oxidation catalysts for CO, C3H6, and NO oxidation
    (TÜBİTAK, 2021) Yıldız, Deniz Şanlı; Özener, Hüseyin Barkın; Hisar, Gökhan; Department of Chemical and Biological Engineering; Güneş, Hande; Bozbağ, Selmi Erim; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; N/A; N/A; 29633
    Four commercial monolithic diesel oxidation catalysts (DOCs) with two different platinum group metal (PGM) loadings and Pt:Pd ratios of 1:0, 2:1, 3:1 (w/w) were investigated systematically for CO, C3H6, and NO oxidation, CO-C3H6 co-oxidation, and CO-C3H6-NO oxidation reactions via transient activity measurements in a simulated diesel engine exhaust environment. As PGM loading increased, light-off curves shifted to lower temperatures for individual and co-oxidation reactions of CO and C3H6. CO and C3H6 were observed to inhibit the oxidation of themselves and each other. Addition of Pd to Pt was found to enhance CO and C3H6 oxidation performance of the catalysts while the presence and amount of Pd was found to increase the extent of self-inhibition of NO oxidation. NO inhibited CO and C3H6 oxidation reactions while NO oxidation performance was enhanced in the presence of CO and C3H6 probably due to the occurrence of reduced Pt and Pd sites during CO and C3H6 oxidations. The optimum Pt:Pd ratio for individual and co-oxidations of CO, C3H6, and NO was found to be Pt:Pd = 3:1 (w/w) in the range of experimental conditions investigated in this study.
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    PublicationOpen Access
    A remarkable class of nanocomposites: aerogel supported bimetallic nanoparticles
    (Frontiers, 2020) Özbakır, Yaprak; Department of Chemical and Biological Engineering; Güneş, Hande; Barım, Şansım Bengisu; Yousefzadeh, Hamed; Bozbağ, Selmi Erim; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; 29633
    Aerogels are a unique class of materials due to their low density, high porosity, high surface area, and an open and interconnected pore structure. Aerogels can be organic, inorganic and hybrid with a plethora of surface chemistries. Aerogel-based products for thermal insulation are already in the market and many studies are being conducted in many laboratories around the world to develop aerogel-based products for other applications including catalysis, adsorption, separations, and drug delivery. On the other hand, bimetallic nanoparticles dispersed on high surface area carriers, which have superior properties compared to their monometallic counterparts, are used or are in development for a wide variety of applications in catalysis, optics, sensing, detection, and medicine. Investigations on using aerogels as high surface area carriers for dispersing bimetallic nanoparticles are leading to development of new composite materials with outstanding properties due to the remarkable properties of aerogels. The review focuses on the techniques to synthesize these materials, their properties, the techniques to tune their pore properties and surface chemistry and the applications of these materials.