Enhanced CO2-Assisted Dehydrogenation of Ethane over Highly Dispersed Chromium Moieties

CO2-assisted ethane dehydrogenation (CO2-EDH) provides an attractive route to ethylene, yet its practical efficiency is limited by nonselective cracking, coke formation, and irreversible reduction of active Cr species. Here, a series of highly dispersed chromium catalysts (Cr@S-1) was prepared by a cetyltrimethylammonium bromide (CTAB)-assisted one-pot strategy. Their catalytic performance for CO2-EDH to ethylene was evaluated. XRD, XPS, UV-vis, Raman, and H2-TPR analyses indicate that the CTAB-mediated synthesis environment regulates MFI crystallization and chromium precursor distribution, leading to improved Cr dispersion and an enhanced population of Cr6+species. The optimized catalyst delivered 69.8% initial ethane conversion and 54.7% ethylene yield at 650 °C without any observable deactivation over 70 h after the induction period, exhibiting better catalytic performance than the conventional impregnated counterpart (Cr/S-1). These results identify surfactant-regulated zeolite encapsulation as an effective route to prepare stable and selective Cr-based catalysts for CO2-assisted ethane dehydrogenation.