Cobalt phthalocyanine coordinated to pyridine-functionalized carbon nanotubes with enhanced CO2 electroreduction

Electrochemical reduction of CO2 is promising to utilize the intermittent renewable electricity and transform CO2 into value-added products, simultaneously. Herein, we designed a cobalt phthalocyanine-based catalyst supported on pyridine-functionalized carbon nanotubes (CoPc-py-CNT). This novel hybrid catalyst exhibited a high activity (TOFCO: 34.5 s−1 at −0.63 V vs. RHE) and selectivity (FECO > 98%) for electrochemical CO2 reduction. To the best of our knowledge, it is the best one among all reported molecular based electrocatalysts for CO2-to-CO conversion. Furthermore, structure characterizations (such as Raman and X-rays photoelectron spectroscopy), loading-dependent electrochemical analysis and mechanistic studies revealed that pyridine groups, through axial coordination with Co, not only functioned as physical promoters to improve the dispersion of cobalt phthalocyanine but also tuned the electronic structure of Co sites to increase the intrinsic turnover frequency.