Insight on the stability of iron phthalocyanine/carbon nanotube hybrid catalysts for the electrochemical carbon dioxide reduction reaction

Abstract

In recent years, the electrochemical conversion of carbon dioxide (CO2) through the electrochemical CO2 reduction reaction (ECO2RR) has attracted considerable attention due to the characteristics of utilizing secondary energy electricity as the driving force and being able to convert CO2 into high-value chemical products. Until now, various catalysts have been developed. Because of the clear molecular structure and well-defined metal active center, metal phthalocyanines (MPcs) are one of the most attractive catalysts and have been widely used in the research of reaction mechanisms. A series of strategies are employed to adjust and optimize their catalytic performance for ECO2RR, including changing the metal center atom, forming hybrid catalysts, adding substituents, forming polymers, and so on. However, these strategies mainly focus on enhancing the activity and selectivity of MPcs, and the research on stability is severely lacking. In order to fill this research gap, I successfully synthesized the hybrid catalysts of FePc/CNT and FePc-NO2/CNT through a simple physical mixing method. Experimental results demonstrate that the introduction of -NO2 substituents improves the catalytic performance of ECO2RR. FePc-NO2/CNT shows a higher activity, selectivity, and stability than FePc/CNT. Finally, the reasons for poor reaction stability are discussed, confirming that the main cause of catalyst deactivation is metal leaching, while the strong adsorption of intermediates is a secondary factor. This work provides guidance for adjusting the performance of MPc-based catalysts and studying their deactivation mechanisms