李修仪, 申浩伟, 徐家乐, 李春义. Cr-MIL-101介导的纳米Cr2O3高效催化正己烷脱氢反应研究[J]. 燃料化学学报(中英文). DOI: 10.1016/S1872-5813(24)60458-5
引用本文: 李修仪, 申浩伟, 徐家乐, 李春义. Cr-MIL-101介导的纳米Cr2O3高效催化正己烷脱氢反应研究[J]. 燃料化学学报(中英文). DOI: 10.1016/S1872-5813(24)60458-5
LI Xiuyi, SHEN Haowei, XU Jiale, LI Chunyi. Cr-MIL-101 derived nano-Cr2O3 for highly efficient dehydrogenation of n-hexane[J]. Journal of Fuel Chemistry and Technology. DOI: 10.1016/S1872-5813(24)60458-5
Citation: LI Xiuyi, SHEN Haowei, XU Jiale, LI Chunyi. Cr-MIL-101 derived nano-Cr2O3 for highly efficient dehydrogenation of n-hexane[J]. Journal of Fuel Chemistry and Technology. DOI: 10.1016/S1872-5813(24)60458-5

Cr-MIL-101介导的纳米Cr2O3高效催化正己烷脱氢反应研究

Cr-MIL-101 derived nano-Cr2O3 for highly efficient dehydrogenation of n-hexane

  • 摘要: 通过热解大比表面Cr-MIL-101制备纳米Cr2O3n-Cr2O3),考察其催化正己烷脱氢反应性能,并比较与沉淀法p-Cr2O3-1、焙烧铬盐得到的p-Cr2O3-2以及工业Cr2O3/Al2O3催化正己烷脱氢活性差异。n-Cr2O3能够催化正己烷高效脱氢为己烯和苯,并且其催化脱氢活性与焙烧温度有关。600 ℃焙烧的n-Cr2O3催化正己烷脱氢转化率最高40.6%,对产物己烯和苯的选择性分别为20.1%和69.3%。提高焙烧温度,n-Cr2O3催化正己烷脱氢活性下降但稳定性增强,催化剂积炭量减少。p-Cr2O3-1和p-Cr2O3-2催化正己烷脱氢转化率很低(<7.5%),比活性分别为1.5和1.7 g/(m2·h),低于n-Cr2O3-600的(2.0 g/(m2·h))。通过BET、XRD、TEM和FT-IR等表征发现,n-Cr2O3为具有较大比表面的纳米颗粒(10−20 nm),多暴露晶面和脱氢活性位,而p-Cr2O3是比表面非常小的大颗粒,所暴露脱氢活性位少。相比之下,Cr2O3/Al2O3催化剂由于大比表面Al2O3的分散作用,催化正己烷脱氢效率更高(2.4 g/(m2·h))。因此,由Cr-MIL-101焙烧得到的n-Cr2O3催化正己烷脱氢的高活性源于这种纳米Cr2O3所具有的独特性质:小颗粒,大比表面,多暴露活性位。

     

    Abstract: Nano Cr2O3 (n-Cr2O3) was prepared by the thermolysis of the mesoporous Cr-MIL-101, and its catalytic performance for n-hexane dehydrogenation was investigated and compared with Cr2O3 obtained by traditional method. It is found that dehydrogenation of n-hexane on n-Cr2O3 catalyst can produce n-hexenes and benzene efficiently, and the catalytic performance is related to the calcination temperature. The optimal n-hexane conversion can be obtained on n-Cr2O3 calcinated under 600 ℃, is 40.6%, and the selectivities to n-hexenes and benzene are 20.1% and 69.3%, respectively. The conversion of n-hexane for n-Cr2O3 catalyst is decreased with calcination temperature, while the catalyst stability in dehydrogenation reaction is enhanced. n-Hexane conversion of p-Cr2O3-1 (obtained by precipitation method) and p-Cr2O3-2 (calcinating Cr(NO3)·9H2O directly) catalysts are very low (<7.5 %), and their specific activity for n-hexane dehydrogenation are 1.5 and 1.7 g/(m2·h) respectively, lower than that of n-Cr2O3-600 (2.0 g/(m2·h)). The results of BET, XRD, TEM and FT-IR reveal that n-Cr2O3 is the nanoparticles with large specific surface area that more dehydrogenation active sites are exposed, while p-Cr2O3 is the large particles with extremely low surface area that few dehydrogenation active sites are presented. By contrast, industrial Cr2O3/Al2O3 catalyst possesses the highest specific activity of 2.4 g/(m2·h) due to the dispersion effect of Al2O3. Therefore, highly catalytic activity of n-Cr2O3 for n-hexane dehydrogenation is attributed to the unique properties of small particle, large specific surface area and more exposed active sites. This work not only explains the high dehydrogenation activity of nano-Cr2O3 derived by Cr-MIL-101, but also provides guidance for the precise design and synthesis of high-performance CrOx-based catalyst for the dehydrogenation of alkanes.

     

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