Abstract:

After the discovery of the dehydrogenation activity of Sn- and Pb-based catalysts, Ge, in the same main group, has also been confirmed to have catalytic activity for propane dehydrogenation. In this study, the In species were introduced into Ge/SiO₂ catalysts by silica sol-gel method, and the effects of In species and their amounts on the dehydrogenation performance of Ge/SiO₂ catalyst were investigated. In addition, various characterization techniques, such as XRD, XRF, N₂ adsorption-desorption, XPS, TEM, and H₂-TPR were used for reaction optimization. The results showed that In₂(Ge₂O₇) was formed and relatively stable during the reaction, which could efficiently inhibit the reduction and sintering of Ge species. The introduction of In species not only could lower the deactivation rate of Ge/SiO₂ catalyst in single reaction, but also could weaken the irreversible deactivation during reaction-regeneration cycles. As a result, the deactivation rate parameter could be decreased from 0.044h^-1 to 0.019h^-1 after introducing of 6 wt% In species, and the initial activity of the regenerated 6In10Ge/SiO₂ catalyst was only decreased by 7.1% as compared with 22.3% of the regenerated 10Ge/SiO₂ catalyst.

Key words: Ge/SiO₂ catalyst, stability, geometrical effect, propane dehydrogenation, silica sol-gel method

摘要：

继Sn、Pb脱氢活性发现之后，同主族的Ge也被证实具有催化丙烷脱氢的能力。本文通过硅溶胶法将In物种引入Ge/SiO₂催化剂，考察了In物种以及In物种含量对Ge/SiO₂催化剂丙烷脱氢性能的影响，并辅以X射线衍射、X射线荧光光谱分析、N₂吸脱附、X射线光电子能谱、透射电子显微镜、H₂程序升温还原等表征方法对其优化原理进行了探讨。研究结果表明，助剂In引入后可生成在反应条件下稳定存在的In₂(Ge₂O₇)，其几何效应削弱了Ge物种的还原与烧结。In物种引入不仅可减缓Ge/SiO₂催化剂单次反应的失活速率，也可削弱多次反应-再生过程中催化剂的不可逆失活。引入6%（质量分数）的In物种后，Ge/SiO₂催化剂的失活速率参数由0.044h^-1降为0.019h^-1，氧化再生后催化剂初始活性也由下降22.3%削弱为仅下降7.1%。

关键词: Ge/SiO₂催化剂, 稳定性, 几何效应, 丙烷脱氢, 硅溶胶法