Tuning lattice oxygen reactivity and oxygen-species distribution in cobalt-doped SrCuO₂ for selective chemical looping oxidative dehydrogenation of ethane

Chemical looping oxidative dehydrogenation (CL-ODH) of ethane provides a safer and potentially more energy-efficient route to ethylene than conventional oxygen-fed oxidative dehydrogenation, but its performance critically depends on oxygen carriers that can simultaneously promote C–H activation and suppress deep oxidation. Here, Cobalt-doped SrCuO₂ oxygen carriers were developed to regulate lattice oxygen reactivity and the distribution of oxygen species for selective ethane CL-ODH. Among the prepared materials, 10% Co-SrCuO₂ exhibited the best performance at 750 °C, delivering 48.6% ethane conversion, 94.2% ethylene selectivity, and an ethylene yield of 45.8%, while maintaining stable reactivity over 10 redox cycles. Structural and mechanistic analyses reveal that Co incorporation induces lattice contraction, weakens Cu–O bonding, enhances reducibility, and lowers the apparent activation energy to 98.5 kJ·mol⁻¹. More importantly, cobalt doping increases the proportion of lattice oxygen while suppressing highly reactive electrophilic oxygen species, thereby facilitating selective C–H bond activation and inhibiting ethylene over-oxidation. This work provides mechanistic insight into oxygen-species regulation in redox catalysts and offers an effective strategy for designing oxygen carriers for selective alkane upgrading via chemical looping.