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Full-Text Articles in Physical Sciences and Mathematics
On The Structure Sensitivity Of Co Oxidation On Alumina Supported Pd--Pt Bimetallic Catalysts, Sarp Kaya, Ebru Erunal, Riad Shaltaf, Şi̇nasi̇ Elli̇altioğlu, Deni̇z Üner
On The Structure Sensitivity Of Co Oxidation On Alumina Supported Pd--Pt Bimetallic Catalysts, Sarp Kaya, Ebru Erunal, Riad Shaltaf, Şi̇nasi̇ Elli̇altioğlu, Deni̇z Üner
Turkish Journal of Chemistry
CO oxidation reaction was studied over monometallic and bimetallic palladium--platinum catalysts at 25:75, 50:50, and 75:25 Pd:Pt atomic fractions co-impregnated over a \gamma -Al_2O_3 support. The size of the metal particles, measured by modified hydrogen chemisorption, increased as the Pd fractions in the catalyst increased. The surface compositions and site metal distributions of the catalysts determined from Monte Carlo simulations indicated that Pd atoms segregated to the surface: at low Pd levels, Pd occupied preferentially 6 and 7 coordinated defect-like sites. As the Pd fraction increased, first 8 coordinated (100) and then 9 coordinated (111) planes were populated. At low …
Co Oxidation Over Mono And Bi-Metallic Sequentially Impregnated Pd-Pt Catalysts, Sarp Kaya, Deni̇z Üner
Co Oxidation Over Mono And Bi-Metallic Sequentially Impregnated Pd-Pt Catalysts, Sarp Kaya, Deni̇z Üner
Turkish Journal of Chemistry
The CO oxidation capability of sequentially impregnated Pd-Pt/\gamma -Al_2O_3 bimetallic catalysts was tested. The CO oxidation light-off curves were hierarchically spaced between monometallic Pd and monometallic Pt, which showed the highest and lowest activity, respectively, indicating that sequential impregnation did not result in the formation of bimetallic particles, but that the catalysts remained as monometallic entities over the support surface. An investigation of the effect of CO partial pressure on the reaction rates over monometallic catalysts indicated that in the presence of excess CO the surface of Pt was poisoned. On the other hand, in the presence of excess CO …
Kinetic Study Of Selective Co Oxidation Over Pt-Co-Ce/Al_2o_3 Catalyst In Hydrogen-Rich Streams, Göktuğ Nezi̇hi̇ Özyönüm, Ayşe Ni̇lgün Akin, Ramazan Yildirim
Kinetic Study Of Selective Co Oxidation Over Pt-Co-Ce/Al_2o_3 Catalyst In Hydrogen-Rich Streams, Göktuğ Nezi̇hi̇ Özyönüm, Ayşe Ni̇lgün Akin, Ramazan Yildirim
Turkish Journal of Chemistry
The kinetics of the selective CO oxidation was studied in a fixed-bed microreactor at atmospheric pressure over Pt-Co-Ce/Al_2O_3 catalyst, which was prepared using the incipient to wetness co-impregnation technique. Intrinsic kinetic data were obtained in the initial rate region using 8 different sets of CO and O_2 concentrations, each at 2 space times, i.e. 2 catalyst loadings, at 110 °C. The kinetic models based on elementary reaction steps were constructed and tested using nonlinear regression analysis with Levenberg-Marquardt algorithm. The alternative models proposed for the similar catalytic systems in the literature were also tested. It was found that Pt-Co-Ce/Al_2O_3 acts …
Characterization And Co Oxidation Activity Studies Of Co-Based Catalysts, Fi̇li̇z Balikçi, Çi̇ğdem Güldür
Characterization And Co Oxidation Activity Studies Of Co-Based Catalysts, Fi̇li̇z Balikçi, Çi̇ğdem Güldür
Turkish Journal of Chemistry
Cobalt oxide based catalysts were developed for carbon monoxide oxidation at low temperature. The catalysts were prepared by co-precipitation and calcined at 200 °C. Several techniques were used to characterize the catalysts, such as X-ray diffractometer system, N_2 physisorption measurements, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy. Carbon monoxide oxidation studies were carried out to investigate the relation between the characteristic properties of the catalysts and the catalytic activity. Catalytic activity measurements were studied from room temperature to 200 °C, using a feed composition of 1% CO, 21% O_2, and remaining He. X-ray studies showed that the catalysts have …
The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu
The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu
Turkish Journal of Chemistry
The effect of metal loading on structural properties and CO oxidation activity of coprecipitated Co/Al_2O_3 catalysts was investigated. The results indicated the participation of cobalt in the Co-Al skeleton for all coprecipitated samples. Environmental-SEM-EDXS studies showed that at loadings higher than ca. 15 wt.-%, cobalt formed layer-by-layer clusters on the surface; 16.8 wt.-% Co/Al_2O_3 displayed the highest activity and stability in CO oxidation.