Effect of Li additive on CO2 hydrogenation reactivity of zeolite supported Rh catalysts
Effect of Li additive on CO2 hydrogenation reactivity of zeolite supported Rh catalysts
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DOI：
10.1016/s0926-860x(98)00202-6
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发表时间：
1998-12
影响因子：
5.5
通讯作者：
K. Bando;K. Soga;K. Kunimori;H. Arakawa
中科院分区：
文献类型：
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作者：
K. Bando;K. Soga;K. Kunimori;H. Arakawa
我们在Li促进的Rh离子交换沸石催化剂(Li/RHY)上进行了CO2加氢反应。随着Li加入量的增加，主要产物由甲烷转化为CO。同时，我们观察到乙醇产量的增加，以及甲醇产量的增加。在Li/Ry(Li/Rh=10)催化剂上，当CO的质量分数为1.8%时，乙醇的选择性可提高到13%，而对Rh离子交换沸石催化剂(Rh=10)的选择性影响不大。通过原位FT-IR观察，研究了Li的促进作用机理。观察到了CO/CO2吸附的红外光谱和后续TPR的红外光谱。在RHY上，CO2分子以CO末端物种的形式被吸附，这与CO吸附的结果相同。而在Li/RHy(Li/Rh=10)上，CO_2吸附在1618 cm−处出现了一个新的峰，形成了相对稳定的物种。结果表明，Li在催化剂表面开辟了一条新的反应路径，促进了CO_2的吸附，稳定了CO吸附物种。
We performed CO2hydrogenation over Li-promoted Rh ion-exchanged zeolite catalysts (Li/RhY). As the amount of added Li increased, the main product transformed from methane to CO. Simultaneously, we observed promotion of ethanol production, as well as methanol production. Moreover, when 1.8% of CO was mixed with the reactant gas, the selectivity for ethanol was increased to as high as 13% on Li/RhY (Li/Rh=10), but no influence was observed on Rh ion-exchanged zeolite catalyst (RhY). We studied the mechanism of the promotion effect of Li by means of in situ FT-IR observations. IR spectra of CO/CO2adsorption and those for subsequent TPR were observed. On RhY, CO2molecules were adsorbed as terminal CO species which were the same as those found in CO adsorption. However, on Li/RhY, a new peak appeared at 1618cm−1by CO2adsorption and relatively stable species were formed on Li/RhY (Li/Rh=10). The results indicate that the Li additives created a new reaction path on the catalyst surface, where CO2adsorption enhancement as well as stabilization of adsorbed CO species occurred.