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Component regulation in novel La-Co-O-C composite catalyst for boosted redox reactions and enhanced thermal stability in methane combustion.
- Source :
-
Journal of environmental sciences (China) [J Environ Sci (China)] 2023 Apr; Vol. 126, pp. 459-469. Date of Electronic Publication: 2022 Apr 15. - Publication Year :
- 2023
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Abstract
- A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation. It was demonstrated that Co <subscript>3</subscript> O <subscript>4</subscript> phase was the main component in regulation. The combined results of X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of oxygen (O <subscript>2</subscript> -TPD), temperature-programmed reduction of hydrogen (H <subscript>2</subscript> -TPR), temperature-programmed desorption of ammonia/carbon dioxide (NH <subscript>3</subscript> /CO <subscript>2</subscript> -TPD) revealed that component regulation led to more oxygen vacancies and exposure of surface Co <superscript>2+</superscript> , lower surface basicity and optimized acidity, which were beneficial for adsorption of active oxygen species and activation of methane molecules, resulting in the excellent catalytic oxidation performance. Especially, the (3.5)LC-C (3.5 is Co-to-La molar ratio) showed the optimum activity and the T <subscript>50</subscript> and T <subscript>90</subscript> (the temperature at which the CH <subscript>4</subscript> conversion rate was 50% and 90%, respectively) were 318 and 367°C, respectively. Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spectroscopy characterization, it was also found that the catalytic mechanism changes from the "Rideal-Eley" mechanism to the "Two-term" mechanism depending on the temperature windows in which the reaction takes place. Besides, the use of the "Flynn-Wall-Ozawa" model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy, further expanding the application scope of carbon-containing composites.<br />Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.<br /> (Copyright © 2022. Published by Elsevier B.V.)
- Subjects :
- Oxidation-Reduction
Catalysis
Oxygen
Methane
Hydrogen
Subjects
Details
- Language :
- English
- ISSN :
- 1001-0742
- Volume :
- 126
- Database :
- MEDLINE
- Journal :
- Journal of environmental sciences (China)
- Publication Type :
- Academic Journal
- Accession number :
- 36503772
- Full Text :
- https://doi.org/10.1016/j.jes.2022.04.002