CO2-affinitive Surface of Metal/Nafion Attributable to Selective Polarization for Superior CO2RR

Abstract

CO₂ reduction reaction (CO₂RR) has been considered as a promising process that can compensate CO₂ emission and convert it into value-added chemicals. In preparation of CO₂RR catalytic electrode, Nafion is a common binder but its effect in catalytic process is usually ignored. Herein, we proposed the bifunction of Nafion in CO₂RR based on its molecular structure and successfully developed a CO₂-affinitive surface of Micro-Ag /Nafion by controlling the content of Nafion, which exhibited a superior CO faradaic efficiency (FE_CO) of 95.07% at -0.9 V (vs. RHE). This excellent FE_CO and 2 times of CO partial current density (j_CO) in flow-cell proved its industrial prospect. Its splendid selectivity of CO₂RR was attributed to the selective polarization of CO₂ molecule at Nafion, which resulted in the 6.8 times higher adsorption energy (E_ads) of CO₂ than H₂O. Therefore, CO₂RR gained an advantage in the competitive reaction.Nafion was recognized as a favorable transporter for CO₂ on the surface of metal catalyst. Our work describes the bifunctional role of Nafion in CO₂RR electrode and it will contribute to optimize the design of metal/Nafion catalytic material for CO₂RR.