Synergistic Catalysis over Iron-Nitrogen Sites Anchored with Cobalt Phthalocyanine for Efficient CO₂ Electroreduction.

Abstract

Simultaneously achieving high Faradaic efficiency, current density, and stability at low overpotentials is essential for industrial applications of electrochemical CO₂ reduction reaction (CO₂ RR). However, great challenges still remain in this catalytic process. Herein, a synergistic catalysis strategy is presented to improve CO₂ RR performance by anchoring Fe-N sites with cobalt phthalocyanine (denoted as CoPc©Fe-N-C). The potential window of CO Faradaic efficiency above 90% is significantly broadened from 0.18 V over Fe-N-C alone to 0.71 V over CoPc©Fe-N-C while the onset potential of CO₂ RR over both catalysts is as low as -0.13 V versus reversible hydrogen electrode. What is more, the maximum CO current density is increased ten times with significantly enhanced stability. Density functional theory calculations suggest that anchored cobalt phthalocyanine promotes the CO desorption and suppresses the competitive hydrogen evolution reaction over Fe-N sites, while the *COOH formation remains almost unchanged, thus demonstrating unprecedented synergistic effect toward CO₂ RR.