The Unique Role of CaO in Stabilizing the Pt/Al 2 O 3 Catalyst for the Dehydrogenation of Cyclohexane

Coke‐induced deactivation is one of the major challenges in the field of heterogeneous catalysis. Herein, the performance of the Pt/Al 2 O 3 catalyst for the hydrogen‐free dehydrogenation of cyclohexane was improved by doping with a small amount of Ca. The Ca‐modified Pt/Al 2 O 3 catalyst exhibited a cyclohexane conversion of 97.0 % and maintained a conversion above 75 % after 48 h, whilst the unmodified catalyst was deactivated from 87.0 to 2.7 % under the same conditions. Characterization techniques, including in situ DRIFT, XPS, thermal analysis, and temperature‐programmed techniques, revealed that the presence of Ca effectively suppressed the deep dehydrogenation of H‐rich carbonaceous components and promoted coke desorption by increasing the H/C ratio of H‐deficient coke. This promotion effect of Ca was also associated with neutralizing the residual Cl ions and promoting immediate dehydrogenation.