Isolation of Highly Reactive Cobalt Phthalocyanine via Electrochemical Activation for Enhanced CO2 Reduction Reaction

Abstract

AbstractElectrochemical CO2‐to‐CO conversion offers an attractive and efficient route to recycle CO2 greenhouse gas. Molecular catalysts, like CoPc, are proved to be possible replacement for precious metal‐based catalysts. These molecules, a combination of metal center and organic ligand molecule, may evolve into single atom structure for enhanced performance; besides, the manipulation of molecules’ behavior also plays an important role in mechanism research. Here, in this work, the structure evolution of CoPc molecules is investigated via electrochemical‐induced activation process. After numbers of cyclic voltammetry scanning, CoPc molecular crystals become cracked and crumbled, meanwhile the released CoPc molecules migrate to the conductive substrate. Atomic‐scale HAADF‐STEM proves the migration of CoPc molecules, which is the main reason for the enhancement in CO2‐to‐CO performance. The as‐activated CoPc exhibits a maximum FECO of 99% in an H‐type cell and affords a long‐term durability at 100 mA cm−2 for 29.3 h in a membrane electrode assembly reactor. Density‐functional theory (DFT) calculation also demonstrates a favorable CO2 activation energy with such an activated CoPc structure. This work provides a different perspective for understanding molecular catalysts as well as a reliable and universal method for practical utilization.