Synthesis of Ce2Sn2O7 pyrochlore and Ce2Sn2O8+x solid solution to support FeOx for simultaneous NH3-SCR and CO oxidation: Study on the paramorphism effect
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Paramorphism effect could be an effective strategy to design efficient catalysts, but has been rarely explored. In this study, to achieve efficient catalysts for elimination of NO and CO together, Ce2Sn2O7 pyrochlore ...
MoreParamorphism effect could be an effective strategy to design efficient catalysts, but has been rarely explored. In this study, to achieve efficient catalysts for elimination of NO and CO together, Ce2Sn2O7 pyrochlore and Ce2Sn2O8+x solid solution paramorphs were purposely synthesized to support FeOx. It is found that Fe/Ce2Sn2O7 displays better reaction performance than Fe/Ce2Sn2O8+x. H2-TPR results have demonstrated that the dispersed FeOx has differed interaction with the two types of supports. Electron paramagnetic resonance (EPR) and density functional theory (DFT) calculation have testified that it is easier to generate surface vacancies on Fe/Ce2Sn2O7 than on Fe/Ce2Sn2O8+x, thus forming more abundant active oxygen sites. Furthermore, the total number of Lewis and Brønsted sites on Fe/Ce2Sn2O7 is larger. In addition, reactive NH4+ linked to Brønsted acidic sites and bridge nitrite are uniquely formed on Fe/Ce2Sn2O7, thus leading to its much better performance than on Fe/Ce2Sn2O8+x. Notably, Fe/Ce2Sn2O7 also exhibits better sulfur and water tolerance. On both catalysts, the NH3-selective catalytic reduction (NH3-SCR) reaction obeys a Langmuir-Hinshelwood pathway, while the CO oxidation follows a Mars-van Krevelen mechanism. In summary, a paramorphism effect is obviously observed, which could give people some new thoughts to design high-performance catalysts.
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Yufeng Yang, ... Xiang Wang
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DOI: https://doi.org/10.70401/smd.2026.0033 - May 12, 2026
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This article belongs to the Special Issue Smart Porous Materials and Catalysis






