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Technical University of Crete
Technical University of Crete
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| URI: | http://purl.tuc.gr/dl/dias/984B8AD9-C092-434B-ADF0-B6211F48EF63 | ||
| Year | 2025 | ||
| Type of Item | Diploma Work | ||
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| Bibliographic Citation | Andreas Pasalopoulos, "Study of the CO2 hydrogenation to CH4, over mono- and bi-metallic Ni and Ru-Ni catalysts supported on mesoporous silicas", Diploma Work, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece, 2025 https://doi.org/10.26233/heallink.tuc.102185 | ||
| Appears in Collections |
The increasing concentration of greenhouse gases, particularly CO2, from human activities, is significantly impacting both humans’ life and various ecosystems. To address this issue, it is essential to develop and implement methods and strategies to mitigate the effects of climate change. One promising approach is Carbon Dioxide Capture and Utilization (CCU), which is a leading technology in current catalysis research. Among the various processes, the Sabatier reaction—where CO2 is hydrogenated to produce methane (CH4)—offers a viable method for recovering and recycling emitted CO2. This process not only aids in reducing CO2 levels in the atmosphere but also supports a decrease in the reliance on fossil fuels. Furthermore, the Sabatier reaction provides a safe way to store and transport hydrogen (H2) through the Power-to-Gas (PtG) process. This solution addresses the safety challenges and high costs often associated with transporting H2 produced from renewable energy sources. The Sabatier reaction is thermodynamically favored at low temperatures, typically between 200–450 °C, which results in high selectivity for CH4. As a result, research has shifted towards developing highly active catalysts that can provide significant CO2 conversion at these low temperatures, where CH4 selectivity usually approaches 100%. The present thesis investigates the catalytic hydrogenation of CO2 by monometallic nickel (Ni) catalysts and bimetallic nickel-ruthenium (Ni-Ru) catalysts, which are supported on MCM-41 mesoporous materials. Initially, porosimetry measurements were conducted to analyze the structural characteristics of the catalysts. The activity, selectivity, and stability of both monometallic (Ni) and bimetallic (Ru-Ni) catalysts were then examined under prolonged operating conditions. The experiments were performed in a fixed-bed reactor with a constant feed composition, maintaining a hydrogen to carbon dioxide ratio (H2/CO2) of 4, in line with the stoichiometry of the Sabatier reaction. The results indicate that increasing the Ni content in the monometallic catalysts enhances CO2 conversion and methane (CH4) production. Additionally, altering the catalyst composition by incrementally replacing Ni with Ru improved the efficiency of the Sabatier reaction. Ultimately, the findings demonstrate that these materials exhibit excellent stability during extended operation.
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