Mechanochemically Prepared Co<sub>3</sub>O<sub>4</sub>-CeO<sub>2</sub> Catalysts for Complete Benzene Oxidation
Considerable efforts to reduce the harmful emissions of volatile organic compounds (VOCs) have been directed towards the development of highly active and economically viable catalytic materials for complete hydrocarbon oxidation. The present study is focused on the complete benzene oxidation as a pr...
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| Autores principales: | , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/ac3cb4eda893460fa916619d043bfd71 |
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| Sumario: | Considerable efforts to reduce the harmful emissions of volatile organic compounds (VOCs) have been directed towards the development of highly active and economically viable catalytic materials for complete hydrocarbon oxidation. The present study is focused on the complete benzene oxidation as a probe reaction for VOCs abatement over Co<sub>3</sub>O<sub>4</sub>-CeO<sub>2</sub> mixed oxides (20, 30, and 40 wt.% of ceria) synthesized by the more sustainable, in terms of less waste, less energy and less hazard, mechanochemical mixing of cerium hydroxide and cobalt hydroxycarbonate precursors. The catalysts were characterized by BET, powder XRD, H<sub>2</sub>-TPR, UV resonance Raman spectroscopy, and XPS techniques. The mixed oxides exhibited superior catalytic activity in comparison with Co<sub>3</sub>O<sub>4</sub>, thus, confirming the promotional role of ceria. The close interaction between Co<sub>3</sub>O<sub>4</sub> and CeO<sub>2</sub> phases, induced by mechanochemical treatment, led to strained Co<sub>3</sub>O<sub>4</sub> and CeO<sub>2</sub> surface structures. The most significant surface defectiveness was attained for 70 wt.% Co<sub>3</sub>O<sub>4</sub>-30 wt.% CeO<sub>2</sub>. A trend of the highest surface amount of Co<sup>3+</sup>, Ce<sup>3+</sup> and adsorbed oxygen species was evidenced for the sample with this optimal composition. The catalyst exhibited the best performance and 100% benzene conversion was reached at 200 °C (relatively low temperature for noble metal-free oxide catalysts). The catalytic activity at 200 °C was stable without any products of incomplete benzene oxidation. The results showed promising catalytic properties for effective VOCs elimination over low-cost Co<sub>3</sub>O<sub>4</sub>-CeO<sub>2</sub> mixed oxides synthesized by simple and eco-friendly mechanochemical mixing. |
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