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NaCl和B2O3在修饰FeOx催化剂中的协同作用
Synergetic Effect between NaCl and B2O3 in Modified FeOx Catalysts
【摘要】 应用连续催化反应,XPS,XRD,H2-TPR,O2-TPD和In-situMossbauer谱等方法表征了一系列组成不同的NaCl/B2O3/Fe2O3催化剂.结果表明NaCl与B2O3在修饰FeOx催化剂上存在明显的协同作用,B2O3调变了FeOx的还原能力,NaCl修饰了B2O3/FeOx使之具有很高的还原速度与晶格氧气化速度.催化剂的催化性能同这种协同作用密切相关.
【Abstract】 A series of NaCl/B2O3/Fe2O3 catalysts having a B/Fe atondc ratio from 0 to 0.3 and 0.25 of Na/Fe atomic ratio were prepared for the oaldative coupling of methane (OCM). It was noted that NaCl and B2O3 show a synergetic effect: NaCl/Fe2O3 produces mainly CO2, but B2O3/ Fe2O3 and B2O3/NaCl have poor activity. NaCl/B2O3/Fe2O3 catalyst has however high activity and selectivity. When the addition of B2O3 approaches 15 (at)%, the C2 yield and selectivity reach their maxima, 17% and 75% respectively. The C2H4/C2 ratio is as high as 76%. XRD, XPS, H2-TPR, O2-TPD and In - situ Mossbauer were employed to investigate the properties of the catalysts. Results show there is a syn ergetic effect between NaCl and B2O3 on FeOx surface. B2O3 modifies the redox ability of Fe2O3. The NaCl modified B2O3/FeOx has high reduction and lattice oxygen evaporation rates at 750℃. The high activity and selectivity of the NaCl/B2O3/FeOx catalyst are closely related with this synergetic effect.
【Key words】 NaCl/B2O3/FeOx catalysts; Synergetic effect; Oxidative coupling of methane; XPS; H2-TPR and O2-TPD;
- 【文献出处】 物理化学学报 ,Acta Physico-chimica Sinica , 编辑部邮箱 ,1994年11期
- 【分类号】O643
- 【被引频次】1
- 【下载频次】67