Preparation and Performance of Ce/Zr Mixed Oxides for Direct Conversion of Methane to Syngas
Ce<,x>Zr<,1-x>O<,2> mixed oxides with different Ce/Zr ratios were prepared by coprecipitation. The characterizations of mixed oxides were studied by X- ray diffraction (XRD) and H<,2>-TPR. And the performances were tested in a fixed-bed quartz reactor. The results indicated that lattice oxygen of Ce<,x>Zr<,1-x>O<,2> could oxidate methane to syngas and the incorporation of zirconium into the ceria lattice could improve the O<2-> mobility. The Ce <,0.7>Zr<,0.3>O<,2> had the best activity in investigative temperature ranging from 600 to 900℃. Effects of reaction time on H<,2>/CO ratio were studied at 850℃ when using Ce<,0.7> Zr<,0.3>O<,2> as catalyst. The results indicated that the ratio was closed to 2 values in the first 10min, however, it rapidly increased with reaction time after>10min. The possible reason was that the direct partial oxidation of methane reaction was dominant in the first 10min. However, the methane pyrogenation was responsible for the rapid increase of H<,2>/CO ratio after 10min. Thus, if syngas with H<,>/CO ratio of 2 wanted to be obtained, the reaction time needed to be controlled.
methane direct conversion cerium zirconium syngas lattice oxygen rare earths
Wei Yonggang(魏永刚) Wang Hua(王华) Li Kongzhai(李孔斋) Liu Mingchun(刘明春) Ao Xianquan(敖先权)
Faculty of Materials and Metallurgy Engineering, Kunming University of Science and Technology, Kunming 650093, China
国际会议
第五届国际稀土开发与应用研讨会(The Fifth International Conference on Rare Earth Decelopment and Applicatin)
包头
英文
110-114
2007-08-07（万方平台首次上网日期，不代表论文的发表时间）