Modulating Co–N Bond Length of CoPc <i>In Situ</i> Grown on Carbon Nanotubes for Efficient CO₂ Electroreduction

The electrochemical reduction of CO2 (CO2RR) to generate high-value fuels presents a promising strategy for addressing the global warming crisis. Cobalt phthalocyanine (CoPc) is a promising CO2 electrocatalyst in which the local electronic environment of the Co–N site plays a key role in regulating the catalytic performance. In this work, CoPc was grown in situ on carbon nanotubes (CNT) via a hydrothermal reaction, resulting in the synthesis of the molecularly dispersed CoPc-CNT catalyst. X-ray absorption fine structure (XAFS) analysis confirmed the presence of Co–N6 ligands with atomically dispersed cobalt in the CoPc-CNT catalyst, which served as active sites for CO2 conversion to CO. The coupling of CoPc and CNT resulted in a reduction of Co–N bond lengths, enhancing the Co–N binding energy and thereby improving catalytic stability. The CO Faradaic efficiency of the CoPc-CNT catalyst, exhibiting excellent stability, reached 99.66% (flow cell) at −1.6 V (vs Ag/AgCl), significantly surpassing that of the CoPc catalyst.