(36c) Oxidative Dehydrogenation of Ethane to Ethylene over Dual-Function Adsorbent/Catalyst Materials

Greenhouse gases and especially CO₂ emissions have greatly contributed into global warming issue. Combined CO₂ capture and utilization has been considered as one of the promising technological solution not only for mitigating CO₂ emissions but also producing good commodity such as chemicals and fuel. In this study, we performed in-situ CO₂ capture and utilization process for ethylene production through oxidative dehydrogenation of ethane in a single bed and semi-isothermal condition with adsorption at 600 ^oC and reaction at 700 ^oC over dual function materials (DFMs) consisting of K-Ca double salt as adsorbent and Cr nanoparticles as catalyst, incorporated on three different supports (SiO₂, H-ZSM-5 SiO₂:Al₂O₃ 200-400 (H-ZSM-5-1), and SiO₂:Al₂O₃ 50 (H-ZSM-5-2). The properties of DFMs were investigated by N₂ physisorption, XRD, XPS, SEM, EDS, NH_3-TPD, H₂-TPR, and thermalgravimetric analysis. The (K-Ca)_40%-(Cr_10%@SiO₂)_60% was found to exhibit the highest C₂H₄ yield of 35.6% followed by (K-Ca@CaO)_40%-(Cr_10%@H-ZSM-5-1)_60% and (K-Ca)_40%/Cr_10%@H-ZSM-5-2)_60% with 30.1% and 25.1%, respectively. These results are in line with Cr⁶⁺/Cr³⁺ ratio obtained by XPS analysis which showed that Cr⁶⁺/Cr³⁺ ratio follows the trend Cr_10%@SiO₂ > H-ZSM-5-1 > H-ZSM-5-2. Overall, this study demonstrated the utility of a combined capture-utilization process for producing light olefins directly from waste CO₂.