Molecular Catalyst Enables CO2 Electroreduction at 650 mA/cm2 CO Partial Current Density

Abstract

The electrochemical reduction of CO₂ to CO using renewable electricity offers a compelling pathway for greenhouse gas recycling. The two-electron, two-proton process is particularly attractive due to its operational simplicity and scalability, with copper- and silver-based nanomaterials being the most widely studied catalysts as the field approaches industrial maturity. However, achieving the necessary efficiency and stability for practical applications remains a significant challenge. Recently, molecular catalysts immobilized on conductive surfaces with carbon-based inks have emerged as highly tunable hybrid systems capable of remarkable selectivity. In this work, we report that a straightforward cobalt phthalocyanine complex, simply modified with a single trimethylammonium group, delivers outstanding CO₂-to-CO conversion rates and selectivity, reaching a Faradaic efficiency of 93% at a total current density of 700 mA/cm² (j_CO = 650 mA/cm²) at neutral pH. Notably, CO selectivity above 90% was sustained for over 42 h at 150 mA/cm², illustrating the potential of simply designed molecular catalysts for large-scale applications.