Regulation of lattice oxygen reactivity of ZrO2 to promote efficient chemical looping oxidative dehydrogenation of ethane
Tao Zhang, Tatiana Otroshchenko, Vita A. Kondratenko, Stephan Bartling, Evgenii V. Kondratenko
Abstract
The development of efficient catalysts for ethane dehydrogenation (EDH) to ethylene remains a challenge due to the lack of direct material property-performance relationships at the most elementary level. Here, we introduce the first application of ZrO2-based catalysts for EDH in a chemical looping mode. Their performance in the first 1 minute, primarily via the oxidative dehydrogenation, highlights their potential for large-scale ethylene production. LaZrOx achieves a space-time yield of 2.26 $${{\mbox{kg}}}_{{{\mbox{C}}}_{2}{{\mbox{H}}}_{4}}\cdot {{\mbox{kg}}}_{{\mbox{cat}}}^{-1}\cdot {{\mbox{h}}}^{-1}$$ at about 80% ethylene selectivity and 50% ethane conversion at 700 °C. Mechanistic studies have identified the reactivity and availability of lattice oxygen as crucial descriptors for mitigating coke formation and suppressing combustion reactions. These properties can be tuned by exposing less stable ZrO2 crystal planes or incorporating metal-oxide promoters. Strongly adsorbed oxygen species can also participate in ethane oxidation. Thus, this study establishes a catalyst system for chemical looping EDH and provides insights for designing more efficient EDH catalysts. Ethane dehydrogenation faces efficiency challenges due to limited structure–performance understanding. Here, bulk ZrO₂-based chemical looping catalysts with tuning lattice oxygen reactivity achieves high ethylene yield and selectivity.