Confinement effect on the electrochemical CO2 reduction reaction

Abstract

The CO₂ electrochemical reduction reaction (CO₂RR) is a promising alternative way to convert CO₂ into high value-added fuels and chemicals with renewable electricity as an energy source to solve the current environmental problems. However, the low catalytic efficiency and poor stability of the CO₂RR are challenges that need to be addressed. In this review, we summarize the advanced progress in the confinement effect on the CO₂RR. In a confined environment, controlled diffusion behaviors of reactants, intermediates and products and charge transfer can effectively facilitate the CO₂RR. Meanwhile, the local increase in pH due to the limited diffusion of the electrolyte and in situ-generated OH⁻ can induce slow proton adsorption kinetics, resulting in inhibition of proton-involving reactions, especially the competitive reaction of hydrogen evolution. Besides, confinement structures can effectively stabilize active metal sites against corrosion, fragmentation, dissolution, agglomeration, and over-reduction due to the protection of limited space or/and confined intermediates. Therefore, attempts to illustrate the relationship between confinement architectures and their catalytic performance are necessary, and they are discussed in this review, and the current challenges and potential strategies for future CO₂RR research are envisioned.