Preparation of double perovskite-type oxide LaSrFeCoO_6 for chemical looping steam methane reforming to produce syngas and hydrogen  

作　　者：赵坤 沈阳 何方 黄振 魏国强 郑安庆 李海滨 赵增立 

机构地区：[1]Key Laboratory of Renewable Energy, Chinese Academy of Sciences, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China [2]Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China [3]Universiiy of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Journal of Rare Earths》2016年第10期1032-1041,共10页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(51406208,51406214);Science & Technology Research Project of Guangdong Province(2013B050800008,2015A010106009)

摘　　要：Double-perovskite type oxide LaSrFeCoO_6 was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Solid-phase, amorphous alloy, sol-gel and micro-emulsion methods were used to prepare the LaSrFeCoO_6 samples, and the as-prepared samples were characterized by means of X-ray diffraction（XRD）, hydrogen temperature-programmed reduction（H_2-TPR）, X-ray photoelectron spectroscopy（XPS）, Brunauer-Emmett-Teller（BET） surface area. Results showed that the samples made by the four different methods exhibited pure crystalline perovskite structure. The ordered double perovskite LaSrFeCoO_6 was regarded as a regular arrangement of alternating FeO_6 and CoO_6 corner-shared octahedra, with La and Sr cations occupying the voids in between the octahedral. Because the La^（3＋） and Sr^（2＋） ions in A-site did not take part in reaction, the TPR patterns showed the reductive properties of the B-site metals. The reduction peaks at low temperature revealed the reduction of adsorbed oxygen on surface and combined with the reduction of Co^（3＋） to Co^（2＋） and to Co^0, while the reduction of Fe^（3＋） to Fe^（2＋） and the partial reduction of Fe^（2＋） to Fe^0 occurred at higher temperatures. From the point of view of the oxygen-donation ability, resistance to carbon formation, as well as hydrogen generation capacity, the sample made by micro-emulsion method exhibited the best reactivity. Its redox reactivity was very stable in ten successive cycles without deactivation. Compared to the single perovskite-type oxides LaFeO_3 and LaCoO_3, the double perovskite LaSrFeCoO_6 exhibited better syngas and hydrogen generation capacity.Double-perovskite type oxide LaSrFeCoO_6 was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Solid-phase, amorphous alloy, sol-gel and micro-emulsion methods were used to prepare the LaSrFeCoO_6 samples, and the as-prepared samples were characterized by means of X-ray diffraction（XRD）, hydrogen temperature-programmed reduction（H_2-TPR）, X-ray photoelectron spectroscopy（XPS）, Brunauer-Emmett-Teller（BET） surface area. Results showed that the samples made by the four different methods exhibited pure crystalline perovskite structure. The ordered double perovskite LaSrFeCoO_6 was regarded as a regular arrangement of alternating FeO_6 and CoO_6 corner-shared octahedra, with La and Sr cations occupying the voids in between the octahedral. Because the La^（3＋） and Sr^（2＋） ions in A-site did not take part in reaction, the TPR patterns showed the reductive properties of the B-site metals. The reduction peaks at low temperature revealed the reduction of adsorbed oxygen on surface and combined with the reduction of Co^（3＋） to Co^（2＋） and to Co^0, while the reduction of Fe^（3＋） to Fe^（2＋） and the partial reduction of Fe^（2＋） to Fe^0 occurred at higher temperatures. From the point of view of the oxygen-donation ability, resistance to carbon formation, as well as hydrogen generation capacity, the sample made by micro-emulsion method exhibited the best reactivity. Its redox reactivity was very stable in ten successive cycles without deactivation. Compared to the single perovskite-type oxides LaFeO_3 and LaCoO_3, the double perovskite LaSrFeCoO_6 exhibited better syngas and hydrogen generation capacity.

关 键 词：double-perovskite CL-SMR micro-emulsion oxygen species redox rare earths 

分 类 号：TQ116.2[化学工程—无机化工] TE665.3[石油与天然气工程—油气加工工程]