Molecular Catalyst with Near 100 Selectivity for CO_2 Reduction in Acidic Electrolytes

摘要

The electrocatalytic carbon dioxide reduction reaction (CO_2RR) 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_2RR 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_2RR 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_2RR 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.