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本文报导了傅里哀变换红外发射光谱法研究多相氧化物催化剂的实验装置的建立及实验条件的考察。设计加工了一个温度范围宽,可在各种气氛和真空条件下原位研究氧化物催化剂的红外发射池。以MoO_3为例,考察了样品厚度,测试温度对发射光谱的影响。当样品量小于1mm·cm~(-2)时,随样品量增加,谱峰强度线性增加,但峰形不发生变化。当样品量高于1mg.cm~(-2)时,随样品量增加,谱图严重畸变。随样品温度升高,谱峰强度近似线性增加。并用该方法研究了MoO_3在还原和再氧化过程中表面氧物种的变化。结果表明桥式MO?O?Mo物种比端基Mo=O物种较易还原,再氧化时,Mo=O物种比Mo?O?Mo物种优先形成。
This paper reports the establishment of an experimental apparatus for the study of heterogeneous oxide catalysts by Fourier transform infrared emission spectroscopy and the investigation of experimental conditions. A wide temperature range was designed and manufactured to investigate oxide catalysts in situ in various atmospheres and under vacuum conditions. Taking MoO_3 as an example, the effects of sample thickness and test temperature on the emission spectra were investigated. When the sample volume is less than 1mm · cm -2, the peak intensity increases linearly with the increase of sample volume, but the peak shape does not change. When the sample volume is higher than 1mg.cm ~ (-2), with the increase of sample size, the spectrum is seriously distorted. As the sample temperature increases, the peak intensity increases approximately linearly. The changes of surface oxygen species during the reduction and reoxidation of MoO_3 were studied by this method. The results show that the bridge MO O Mo species is more reducible than the terminal Mo O species, and the Mo O species is preferentially formed than the Mo O Mo species when reoxidized.