摘要
用原位红外光谱和程序升温还原技术考察了甲醇在Ｒｈ－Ｍｏ／ＳｉＯ２催化剂上的吸附和还原性能。红外结果表明，甲醇在ＳｉＯ２上的主要以分子形式吸附，Ｒｈ／ＳｉＯ２和Ｒｈ－Ｍｏ／ＳｉＯ２在室温下甲醇分解就有活性，分解生成的ＣＯ以线式和桥式吸附态存在，在５７３Ｋ下用甲醇处理后，Ｒｈ／ＳｉＯ２上ＣＯ线式和桥式谱带分别位于２０５０和１９０７ｃｍ＾－１。
Rh/SiO2 catalysts with Mo promoter were studied by in-situ FTIR and TPR techniques. Methanol is adsorbed on SiO2 mainly in molecular form. Rh/SiO2 and Rh-Mo/SiO2 are active for CH3OH decomposition even if at room temperature. After being treated with CH3OH at 573 K, Rh/SiO2shows IR bands of linear and bridged CO at 2050 and 1907 cm-1 respectively. Meanwhile, Rh-Mo (1: 1)/SiO2 has a weaker linear CO band at 2 036cm-1 and a' very weak bridged CO. Added Mo may cover parts of Rh surfaceand thus decrease the IR band intensity of CO and prohibit the formation ofbridged CO species. TPR results indicate that Mo becomes easier while Rhbecomes more difficult to be reduced with the addition of Mo onto Rh/SiO2.In Rh-Mo/SiO2 catalysts, Rh may exist in three forms which are halide formand two oxide forms with low and high reduction temperature, respectively.
出处
《催化学报》
CSCD
北大核心
1996年第2期101-105,共5页
基金
国家自然科学基金
关键词
铑
二氧化硅
红外光谱
甲醇
吸附性能
hodium
silica
molybdenum promoter
Fourier transforminfrared spectroscopy
temperature-programmed reduction
methanol adsorption
