Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Subject: search.filters.subject.Catalytic activityWoS Q: search.filters.wosQuartile.Q1

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  • Article
    Citation - WoS: 38
    Citation - Scopus: 43
    Characterization and Performance Evaluation of Pt[sbnd]ru/C[sbnd]tio2 Anode Electrocatalyst for Dmfc Applications
    (Elsevier Ltd., 2017) Erçelik, Mustafa; Özden, Adnan; Şeker, Erol; Çolpan, C. Özgür
    In this study, the effect of introduction of titania (TiO2) material into Pt[sbnd]Ru/C anode electrocatalyst on the performance of direct methanol fuel cells (DMFCs) was investigated. TiO2 materials were first synthesized applying a sol–gel method and then incorporated directly into commercial Pt[sbnd]Ru/C anode electrocatalyst with different TiO2 weight ratios (5, 15, and 25 wt.%) to improve the performance of the DMFC. For comparison, the anode electrocatalysts with the same TiO2 weight ratios were also prepared using commercial TiO2 materials. The performance tests of the DMFCs based on these composite anode electrocatalysts were conducted and their performances were also compared to that of a DMFC based on a traditional anode electrocatalyst (Pt[sbnd]Ru/C) under various operating conditions. In addition, 4 h short-term stability tests were conducted for all the manufactured DMFCs. The highest power densities were found as 705.12 W/m2 and 709.32 W/m2 at 80 °C and 1 M for the DMFCs based on Pt[sbnd]Ru/C[sbnd]TiO2 anode electrocatalysts containing 5 wt.% of commercial and in-house TiO2, respectively. The results of the short-term stability tests showed that introduction of 5 wt.% of commercial TiO2 into commercial Pt[sbnd]Ru/C anode electrocatalyst improved its stability characteristics significantly.
  • Article
    Citation - WoS: 88
    Citation - Scopus: 108
    Biomimetic Co2 Sequestration: 1. Immobilization of Carbonic Anhydrase Within Polyurethane Foam
    (American Chemical Society, 2009) Özdemir, Ekrem
    Bovine carbonic anhydrase (CA) was immobilized within polyurethane (PU) foam for biomimetic CO2 sequestration. The catalytic activities for the free and immobilized CA were estimated using paranitrophenyl acetate (p-NPA) as the substrate. Because the p-NPA has limited solubility in the aqueous phase, the activities were estimated in Tris buffer containing 10% acetonitrile. A Lineweaver-Burk relationship was employed to estimate the Michaelis-Menten kinetic parameters for the free and immobilized CA. The kcat, K m, and kcat/Km values for the free CA were found to be 2.02 s-1, 12.2 mM, and 166.4M-1 s-1, respectively. The Km value for the immobilized CA was estimated to be 9.6mMat the same conditions. The immobilized CA was stable and did not lose any activity over seven consecutive washings and activity tests. While the free CA lost its activity in 45 days stored at 4 °C in refrigerator, the immobilized CA maintained 100% of its activity over a 45 day period stored in Tris buffer at ambient conditions. It was concluded that the immobilized CA as a very stable biocatalyst could be employed in biomimetic CO2 sequestration.