Overcoming coke formation in high-temperature CO2 electrolysis

Abstract

AbstractHigh-temperature CO2 reduction reaction (HT-CO2RR) in solid oxide electrochemical cells (SOECs) features near-unity selectivity, high energy efficiency, and industrial relevant current density for the production of CO, a widely-utilized “building block” in today’s chemical industry. Thus, it offers an intriguing and promising means to radically change the way of chemical manufacturing and achieve carbon neutrality using renewable energy sources, CO2, and water. Albeit with the great potential of HT-CO2RR, this carbon utilization approach, unfortunately, has been suffering coke formation that is seriously detrimental to its energy efficiency and operating lifetime. In recent years, much effort has been added to understanding the mechanism of coke formation, managing reaction conditions to mitigate coke formation, and devising coke-formation-free electrode materials. These investigations have substantially advanced the HT-CO2RR toward a practical industrial technology, but the resulting coke formation prevention strategies compromise activity and energy efficiency. Future research may target exploiting the control over both catalyst design and system design to gain selectivity, energy efficiency, and stability synchronously. Therefore, this perspective overviews the progress of research on coke formation in HT-CO2RR, and elaborates on possible future directions that may accelerate its practical implementation at a large scale.