摘要
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。
Fourier-transform infrared(FT-IR) emission spectroscopic technique has been establi-shed to study metal oxide catalysts.An in situ infrared emission cell was specially de-signed to treat sample in vacuo or in various gases at a wide temperature range(r.t.-700℃). Infrared emission spectrum of MoO_3 was presented and the results demons-trated that FT-IR emission spectroscopy is a sensitive method to detect vibrationalinformation of metal oxide catalysts.The experimental conditions including samplepreparation, effects of temperature and sample thickness on the infrared emissionspectrum were detailed.It was found that the spectrum was severely disordered whenthe sample thickness of MoO_3 was beyond 1.00mg·cm^2 and the more intensive emi-ssion bands were detected at higher temperatures.Infrared emission spectra recordedin the course of H^2 reduction of MoO_3 showed that surface linkage Mo-O-Mo speciesgiving the band at 880 cm^(-1) is more easily reduced comparing to the terminal Mo=Ospecies giving the band at 990 cm^(-1), vice versa,the Mo=O species are preferentiallyformed than the Mo-O-Mo species during the reoxidation of the partially reducedMoO_3.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1992年第1期64-69,共6页
Acta Physico-Chimica Sinica
关键词
氧化钼
催化剂
氧化-还原
IR光谱
FT-IR Emission spectroscopy
Molybdenum Oxide
Oxidation-Reduction
Infrared Emission Spectroscopy
Catalyst Characterization
