Insight on Performance Degradation of Phthalocyanine Cobalt-Based Gas Diffusion Cathode for Carbon Dioxide Electrochemical Reduction

Abstract

Phthalocyanine is a type of non-noble metal electrocatalyst that efficiently and selectively produces CO from CO2. Herein, we studied the durability of a cobalt phthalocynine (CoPc)-based gas diffusion electrode (GDE) in a flow cell. This is the first report on the degradation mechanism of the CoPc-based GDE for CO2 electrochemical reduction. Leaching of CoPc and demetalation of phthalocyanine are observed, and the interaction between CoPc and carbon black becomes weaker after a durability test. More seriously, part of the micropores of the GDE which act as mass transfer channels of reactants and products collapse, and the hydrophobicity of the catalyst layer of the GDE is almost destroyed. This means that the mass transfer properties of the GDE undergo tremendous changes. To enhance the durability of CoPc-based GDEs, work to prevent the deactivation of the catalyst and improve the solidity of the microstructure of GDEs should be done.