Efficient sorbent/catalyst composites for CO2-mediated oxidative dehydrogenation of ethane via isothermal integrated CO2 capture and utilization

• Performance of dual functional material (DFM) was improved through doping transition metal elements. • The effect mechanism of doping transition metal elements was analyzed in-depth. • The deactivation and regeneration mechanisms of DFM was explored. • The critical mechanism of isothermal integrated CO 2 capture and utilization was summarized. The isothermal integrated CO 2 capture and utilization to produce ethylene (ICCU-ODHE) performances of dual functional materials (DFM) were improved by doping five transition metal elements (Fe, Co, Ni, Cu, Zn). The results show that the DFM doped with Zn exhibits excellent ICCU-ODHE performance with an ethylene yield of 35.1 %. The results based on in-situ XPS and DFT calculation show that the doping transition metal elements can reduce the energy barriers for activating ethane and CO 2 . It is mainly because doping transition metal elements with strong electronegativity can increase the coordinative unsaturated Cr 3+ ions to adsorb more ethane molecules, meanwhile, the doping also reduces the charge density of Cr 3+ and generates additional unfilled electron orbitals facilitating charge transfer to improve the CO 2 and ethane activation. However, the decrease in charge density can increase the difficulty of ethylene desorption and reduce the ethylene selectivity. In addition, the cyclic regeneration experiment shows that the ICCU-ODHE performance of DFM can decrease with the increase of cycles, however, significant performance restoration is achievable after regeneration in the air at 650 °C, attributed to the limited graphitization of coke deposition on the DFM.