Ni–Fe and Co–Fe binary oxides derived from layered double hydroxides and their catalytic evaluation for hydrogen production
Ni–Fe and Co–Fe binary oxides derived from layered double hydroxides and their catalytic evaluation for hydrogen production
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DOI：
10.1016/j.cattod.2014.08.010
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发表时间：
2015-07
期刊：
影响因子：
5.3
通讯作者：
Davi C. Carvalho;N. A. Ferreira;J. Filho;O. Ferreira;J. Soares;Alcineia C. Oliveira
中科院分区：
文献类型：
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作者：
Davi C. Carvalho;N. A. Ferreira;J. Filho;O. Ferreira;J. Soares;Alcineia C. Oliveira
基于 Co-Fe 和 Ni-Fe 的二元氧化物是通过对具有不同 Ni/Fe 和 Co/Ni 比例的层状双氢氧化物 (LDH) 进行热处理合成的。通过X射线衍射(XRD)、拉曼和穆斯堡尔光谱、氮吸附-解吸等温线、程序升温还原(TPR)和CO2程序升温解吸(TPD-CO2)、扫描电子显微镜(SEM)对固体进行了表征，并在甲烷干重整中进行了评估。 XRD结果表明，尖晶石氧化物如NiFe2O4和CoFe2O4与γ-Fe2O3、α-Fe2O3、Co3O4和NiO一氧化物共存。这些相由拉曼光谱和穆斯堡尔光谱证实。氮气吸附-解吸等温线显示孔隙度在微米到中孔范围内，一些样品显示大孔。通过在 650 和 750 °C 范围内改变温度对甲烷干重整进行的催化评估表明，原位形成 Co°/CoFe2O4 和 Ni°/NiFe2O4 相，随着温度的升高，结果最好，导致 H2/CO 比率接近 1。Co-Fe 系列显示出的抗结焦能力特别显着，然而，在这些固体上观察到烧结效应。
Binary oxides based on Co–Fe and Ni–Fe were synthesized thermal treatment of layered double hydroxides (LDH) having distinct Ni/Fe and Co/Ni ratios. The solids were characterized through X-ray diffraction (XRD), Raman and Mössbauer spectroscopy, nitrogen adsorption–desorption isotherms, thermoprogrammed reduction (TPR) and thermoprogrammed desorption of CO2(TPD-CO2), scanning electron microscopy (SEM) and evaluated in dry reforming of methane. XRD results revealed the spinel oxides such as NiFe2O4and CoFe2O4coexisting with γ-Fe2O3, α-Fe2O3, Co3O4and NiO monoxides. These phases were confirmed by Raman and Mössbauer spectroscopy. Nitrogen adsorption–desorption isotherms showed a porosity within micro-to-meso pores range, with some samples displaying macropores. Catalytic evaluation in the dry reforming of methane by varying the temperature in the 650 and 750 °C range suggested in situ Co°/CoFe2O4and Ni°/NiFe2O4phases formation, which gives best results with the temperature increment, resulting in H2/CO ratios close to 1. The elevated resistance to coking showed by Co–Fe series is particularly remarkable, however, sintering effects were observed over these solids.