Electrochemical Activation of Surface Oxygen for Efficient Oxidative Dehydrogenation Reaction at Elevated Temperatures
Xiang Sun, Heejae Yang, Benchi Chen, Mengzhen Zhou, Yongjian Ye, Xiaobao Li, Hui Zhang, Bo Yu, Yifeng Li, Jeong Woo Han, Yan Chen
Abstract
Oxidative dehydrogenation (ODH) of alkane with CO 2 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 Sr 2 Ti 0.8 Co 0.6 Fe 0.6 O 6-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 CO 2 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.