Perspective on electrochemical CO2 reduction in CO2/O2 mixed gas

Abstract

Electrochemical CO₂ reduction reaction (CO₂RR) is a promising avenue to realize carbon neutrality. As the high-purity CO₂ in CO₂RR may diminish the feasibility and economic viability, the direct conversion of CO₂ in O₂-containing feed gas (CO₂/O₂) presents an attractive option. However, high CO₂RR kinetic barriers and the challenges associated with O₂ reduction significantly hamper the effectiveness of CO₂RR. Therefore, enhancing the selective CO₂RR in CO₂–O₂ mixed gas is critical. In this perspective, we first discuss factors of selective CO₂RR in CO₂/O₂. Then, state-of-the-art interface design strategies for the selective CO₂RR, including O₂ passivation, selective CO₂ adsorption and direct selective CO₂RR, are highlighted. Finally, a brief discussion on the current challenges and outlook for future directions to achieve highly efficient and O₂-tolerant CO₂RR systems are presented.