Electrochemical Activation of Surface Oxygen for Efficient Oxidative Dehydrogenation Reaction at Elevated Temperatures

Oxidative dehydrogenation (ODH) of alkane with CO2 as the oxidant has attracted worldwide attention as a promising approach for simultaneously producing valuable alkenes and greenhouse gas utilization. The selectivity and yield of the produced alkene, nevertheless, require further enhancement for practical applications. In this work, taking Sr2Ti0.8Co0.6Fe0.6O6-δ (STCF) as the electrode material, we demonstrate that a solid oxide electrolysis cell (SOEC) can efficiently catalyze the ODH of ethane to ethylene on the anode and reduce CO2 to CO at the cathode. The optimal yield of ethylene reached 66.3% at 800 °C, which is among the highest values reported in the literature. Such ethane ODH activity is attributed to the activation of surface oxygen on the STCF anode by electrolytic voltage, as revealed experimentally by advanced spectroscopic techniques. The density functional theory calculation further implied that the electrochemically driven formation of active oxygen species on the STCF surface upshifts the O 2p-band center, facilitates electron transfer, and enhances surface adsorption, leading to a strongly promoted dehydrogenation process. The results clarify the critical role of oxygen activity in determining the electrochemical ODH performance and can guide the rational design of catalysts for other electrosynthesis processes.