Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis
The determination of the catalyst’s active phase helps improve the catalytic performance of the Fischer–Tropsch (FT) synthesis. Different phases of cobalt, including cobalt oxide, carbide, and metal, exist during the reaction. The content of each phase can affect the catalytic performance and produc...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Catalysts |
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| Online Access: | https://www.mdpi.com/2073-4344/12/10/1222 |
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| author | Zahra Gholami Zdeněk Tišler Eliška Svobodová Ivana Hradecká Nikita Sharkov Fatemeh Gholami |
| author_facet | Zahra Gholami Zdeněk Tišler Eliška Svobodová Ivana Hradecká Nikita Sharkov Fatemeh Gholami |
| author_sort | Zahra Gholami |
| collection | DOAJ |
| description | The determination of the catalyst’s active phase helps improve the catalytic performance of the Fischer–Tropsch (FT) synthesis. Different phases of cobalt, including cobalt oxide, carbide, and metal, exist during the reaction. The content of each phase can affect the catalytic performance and product distribution. In this study, a series of cobalt carbide catalysts were synthesized by exposure of Co/Al<sub>2</sub>O<sub>3</sub> catalyst to CH<sub>4</sub> at different temperatures from 300 °C to 800 °C. The physicochemical properties of the carbide catalysts (CoC<sub>x</sub>/Al<sub>2</sub>O<sub>3</sub>) were evaluated by different characterization methods. The catalytic performances of the catalysts were investigated in an autoclave reactor to determine the role of cobalt carbides on the CO conversion and product distribution during the reaction. XRD and XPS analysis confirmed the presence of Co<sub>2</sub>C in the prepared catalysts. The higher carbidation temperature resulted in the decomposition of methane into hydrogen and carbon, and the presence of graphitic carbon was confirmed by XRD, XPS, SEM, and Raman analysis. The Co<sub>2</sub>C also decomposed to metallic cobalt and carbon, and the content of cobalt carbide decreased at higher carbidation temperatures. Higher content of Co<sub>2</sub>C resulted in a lower CO conversion and higher selectivity to light alkanes, mainly methane. The higher carbidation temperature resulted in the decomposition of Co<sub>2</sub>C to metallic cobalt with higher activity in the FT reaction. The CO conversion increased by increasing the carbidation temperature from 300 °C to 800 °C, due to the higher content of metallic cobalt. In the presence of pure hydrogen, the Co<sub>2</sub>C could be converted mainly into hexagonal, close-packed (hcp) Co with higher activity for dissociative adsorption of CO, which resulted in higher catalyst activity and selectivity to heavier hydrocarbons. |
| first_indexed | 2024-03-09T20:30:13Z |
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| id | doaj.art-81a08df759de4653911637f918e4877b |
| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-09T20:30:13Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
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| series | Catalysts |
| spelling | doaj.art-81a08df759de4653911637f918e4877b2023-11-23T23:25:40ZengMDPI AGCatalysts2073-43442022-10-011210122210.3390/catal12101222Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch SynthesisZahra Gholami0Zdeněk Tišler1Eliška Svobodová2Ivana Hradecká3Nikita Sharkov4Fatemeh Gholami5ORLEN UniCRE, a.s., 436 70 Litvínov, Czech RepublicORLEN UniCRE, a.s., 436 70 Litvínov, Czech RepublicORLEN UniCRE, a.s., 436 70 Litvínov, Czech RepublicORLEN UniCRE, a.s., 436 70 Litvínov, Czech RepublicORLEN UniCRE, a.s., 436 70 Litvínov, Czech RepublicNew Technologies-Research Centre, University of West Bohemia, 301 00 Plzeň, Czech RepublicThe determination of the catalyst’s active phase helps improve the catalytic performance of the Fischer–Tropsch (FT) synthesis. Different phases of cobalt, including cobalt oxide, carbide, and metal, exist during the reaction. The content of each phase can affect the catalytic performance and product distribution. In this study, a series of cobalt carbide catalysts were synthesized by exposure of Co/Al<sub>2</sub>O<sub>3</sub> catalyst to CH<sub>4</sub> at different temperatures from 300 °C to 800 °C. The physicochemical properties of the carbide catalysts (CoC<sub>x</sub>/Al<sub>2</sub>O<sub>3</sub>) were evaluated by different characterization methods. The catalytic performances of the catalysts were investigated in an autoclave reactor to determine the role of cobalt carbides on the CO conversion and product distribution during the reaction. XRD and XPS analysis confirmed the presence of Co<sub>2</sub>C in the prepared catalysts. The higher carbidation temperature resulted in the decomposition of methane into hydrogen and carbon, and the presence of graphitic carbon was confirmed by XRD, XPS, SEM, and Raman analysis. The Co<sub>2</sub>C also decomposed to metallic cobalt and carbon, and the content of cobalt carbide decreased at higher carbidation temperatures. Higher content of Co<sub>2</sub>C resulted in a lower CO conversion and higher selectivity to light alkanes, mainly methane. The higher carbidation temperature resulted in the decomposition of Co<sub>2</sub>C to metallic cobalt with higher activity in the FT reaction. The CO conversion increased by increasing the carbidation temperature from 300 °C to 800 °C, due to the higher content of metallic cobalt. In the presence of pure hydrogen, the Co<sub>2</sub>C could be converted mainly into hexagonal, close-packed (hcp) Co with higher activity for dissociative adsorption of CO, which resulted in higher catalyst activity and selectivity to heavier hydrocarbons.https://www.mdpi.com/2073-4344/12/10/1222Fischer-Tropschcobalt carbideactive phaseproduct distributionmetallic cobalt |
| spellingShingle | Zahra Gholami Zdeněk Tišler Eliška Svobodová Ivana Hradecká Nikita Sharkov Fatemeh Gholami Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis Catalysts Fischer-Tropsch cobalt carbide active phase product distribution metallic cobalt |
| title | Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis |
| title_full | Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis |
| title_fullStr | Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis |
| title_full_unstemmed | Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis |
| title_short | Catalytic Performance of Alumina-Supported Cobalt Carbide Catalysts for Low-Temperature Fischer–Tropsch Synthesis |
| title_sort | catalytic performance of alumina supported cobalt carbide catalysts for low temperature fischer tropsch synthesis |
| topic | Fischer-Tropsch cobalt carbide active phase product distribution metallic cobalt |
| url | https://www.mdpi.com/2073-4344/12/10/1222 |
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