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Low temperature prepared copper-iron mixed oxides for the selective CO oxidation in the presence of hydrogen
Applied Catalysis A: General ( IF 4.7 ) Pub Date : 2017-12-17 , DOI: 10.1016/j.apcata.2017.12.012
M.P. Yeste , H. Vidal , A.L. García-Cabeza , J.C. Hernández-Garrido , F.M. Guerra , G.A. Cifredo , J.M. González-Leal , J.M. Gatica

Copper-iron mixed oxides with Fe/Cu molar ratios ranging from pure CuO to Fe2O3 were synthesised by a low temperature co-precipitation method, and tested in the CO-PROX reaction. The extensive characterization performed by means of different techniques showed the progressive variation of physical and chemical properties including composition, texture, structure and reducibility of the prepared oxides. Rietveld analysis of X-ray diffraction data, XPS and Raman spectra, and especially TEM study revealed the formation of CuFe2O4. All the samples were more active and selective below 200 °C than a commercial Pt/Al2O3 catalyst used as a reference. In particular, the catalyst having a 2 Fe/Cu molar ratio, corresponding to the cuprospinel stoichiometry, exhibited the best performance with a 76% conversion and a 60% selectivity at 125 °C, operating with 50% of H2 in the gas stream, being relatively stable in long-term time-on-stream experiments. On the contrary, pure CuO rapidly deactivated in the course of reaction at 150 °C. Differences in catalytic stability were related to a promoting effect of iron in the mixed oxide which makes copper more resistant to full reduction.



中文翻译:

低温制备的铜-铁混合氧化物,用于在氢气存在下进行选择性CO氧化

采用低温共沉淀法合成了Fe / Cu摩尔比为纯CuO至Fe 2 O 3的铜铁混合氧化物,并在CO-PROX反应中进行了测试。通过不同技术进行的广泛表征显示了物理和化学性质的逐步变化,包括制备的氧化物的组成,织构,结构和可还原性。X射线衍射数据,XPS和拉曼光谱的Rietveld分析,尤其是TEM研究揭示了CuFe 2 O 4的形成。与市售Pt / Al 2 O 3相比,所有样品在200°C以下均具有更高的活性和选择性。用作参考的催化剂。尤其是,具有2 Fe / Cu摩尔比(对应于铜松油化学计量比)的催化剂在125°C下以76%的转化率和60%的选择性表现出最佳性能,在气流中使用50%的H 2时表现出最佳的性能。,在长期的运行时间实验中相对稳定。相反,纯CuO在150°C的反应过程中迅速失活。催化稳定性的差异与混合氧化物中铁的促进作用有关,后者使铜更难以完全还原。

更新日期:2017-12-17
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