ABSTRACT

Porous Yb₂O₃ ceramic (55%) was pressureless sintered at 900°C for four hours in air. The crystal structure of Yb₂O₃ was confirmed to be cubic ($Ia\overline{3}$) with c = 10.43731 Å by neutron diffraction. The spectral vibrational signature of Yb₂O₃ was also confirmed by micro-Raman spectroscopy. Yb₂O₃ is an amphoteric oxide with both acid and base character, which presents the potential for producing different hydrocarbons when used as a Fischer–Tropsch (FT) catalyst. It was found that Yb₂O₃ is indeed catalytically active and can be used to convert syngas (CO + H₂) into useful hydrocarbons. Production of methane, ethene, and ethane was detected in the catalytic experiment performed at 500°C, but propane, propene, butane, and methanol were also detected in the experiment performed at 250°C. Hydrocarbons heavier than C₄ were not observed. The limited data show deviation from a Flory–Schulz distribution suggesting additional surface processes are occurring beyond chain growth and termination.

摘要

多孔 Yb ₂ O ₃陶瓷（55%）在空气中在 900°C 下无压烧结四小时。Yb ₂ O ₃的晶体结构被证实为立方（$\mathrm{一世}\mathrm{一种}\overline{3}$) 中子衍射 c = 10.43731 Å。Yb ₂ O ₃的光谱振动特征也由微拉曼光谱证实。Yb ₂ O ₃是一种兼具酸和碱特性的两性氧化物，当用作费-托 (FT) 催化剂时，它具有生产不同碳氢化合物的潜力。发现 Yb ₂ O ₃确实具有催化活性，可用于转化合成气（CO + H ₂) 转化为有用的碳氢化合物。在 500°C 下进行的催化实验中检测到甲烷、乙烯和乙烷的产生，但在 250°C 下进行的实验中也检测到丙烷、丙烯、丁烷和甲醇。没有观察到比 C ₄重的烃。有限的数据显示了与 Flory-Schulz 分布的偏差，表明除了链增长和终止之外，正在发生额外的表面过程。