通过热解大比表面Cr-MIL-101制备纳米Cr₂O₃（n-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。

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 CrO_x-based catalyst for the dehydrogenation of alkanes.