Adsorbed Oxygen Atoms for Improving the Oxidative Dehydrogenation of Ethane Over B-Site-Doped Layered Perovskite La2ti2o7

Abstract

Ethylene was produced by the oxidative dehydrogenation of ethane (ODHE) over B-site-doped layered perovskite La2Ti2O7. ODHE occurred at a low temperature (500 °C), whereas at higher temperatures, the reactions became more complex because of the thermal activation of thermal dehydrogenation, thermal–oxidative dehydrogenation, and reforming processes. At 650 °C (below 675 °C at which thermal reactions are activated), 36–42% ethylene yield was achieved over B-site-doped layered perovskite La2Ti2O7 in a short reactant–catalyst contact time (within 0.1 s). The B-site dopants Nd, Cd, Ga, and Sm significantly modified the properties of the layered perovskite La2Ti2O7 catalyst, resulting in different performances at 500–625 °C. All doped catalysts exhibited their highest activity at 650 °C or higher temperature. The active sites (adsorbed oxygen or lattice oxygen) for oxidative dehydrogenation are addressed by combining density functional theory calculations and experimental data. The mechanism of ODHE over the catalysts is proposed.

Keywords: oxidative dehydrogenation, ethylene, La2Ti2O7, layered perovskite, density functional theory