Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2012
Student: GÜLÇİN TOPALOĞLU
Supervisor: SENA YAŞYERLİ
Abstract:Reaction of dry reforming of methane with carbon dioxide, has gained importance due to the transformation of the greenhouse effect gases (CH4 and CO2) into synthesis gas (CO, H2) which are usable products. In this study, hydrotalcite (HT) - like catalysts having high surface area and highly stable structures were synthesized. In the first part of the study, Ni-MgAlO catalysts with different Ni/Mg molar ratios were synthesized by co-precipitation method. Then, keeping the Ni amount constant Ni-CaAlO catalysts were synthesized by exchanging Mg in the hydrotalcite structure by Ca and activity tests were performed. Among the catalysts with different Ni/Mg ratios, the most active and stable catalyst was Ni-MgAlO3 (Ni/Mg:0,2) and long term activity tests were then carried out with this catalyst. In order to determine the effect of preparation technique, Ni@MgAlO and Ni@CaAlO were prepared by the impregnation method and tested in the reaction. In the last part of the study, by the addition of 1% by mass of ruthenium to the Ni-CaAlO and Ni-MgAlO catalysts by impregnation method, Ru@ NiMgAlO and Ru@NiCaAlO were prepared and their catalytic activites were tested. In order to determine the structural and physical properties of the prepared catalysts, XRD, BET surface area, and ICP-MS, SEM, TPR and TGA / DTA analyzes were conducted. As a result of the catalytic activity tests, it was observed that H2/CO ratio achieved with Ni-CaAlO catalyst, which was prepared by the co-precipitation method, was approximately one. Ni-MgAlO3 catalyst which was subjected to durability tests for 50 hours of reaction time, kept its activity and the conversions of methane and CO2 achieved with this catalyst were 0.27 and 0.32, respectively. It was observed that, reverse water gas shift reaction lost its significance when the catalyst prepared by impregnation method (Ni@MgAlO1) was used. After the TGA analysis, it was observed that the addition of rutenyum to Ni-MgAlO3 catalyst by the impregnation method decreased the amount of formed carbon from 27% to 18%.