Molecular Catalyst with Near 100% Selectivity for CO2 Reduction in Acidic Electrolytes

Abstract The electrocatalytic carbon dioxide reduction reaction (CO 2 RR) in an acidic medium is conducive to the efficient utilization of CO 2 by preventing the formation of carbonate/bicarbonate. However, acidic media are more favorable for the hydrogen evolution reaction (HER), resulting in unsatisfactory CO 2 RR selectivities. It is demonstrated that the molecularly dispersed electrocatalyst of β‐tetra methoxy‐substituted nickel phthalocyanine on carbon nanotubes (NiPc‐OMe MDE) can efficiently catalyze CO 2 RR in acidic media (pH 2 to 0.47) with Faradaic efficiencies of CO >98% over a wide range of current densities from −50 to −400 mA cm −2 . It is found that the superior selectivity performance can be attributed to the presence of potassium ions, the high preference of CO 2 RR over HER on the active site, and few side reaction sites. The study illuminates the potential of molecular electrocatalysts for selective and rapid reduction of CO 2 in acid media.