The boosting of electrocatalytic CO2-to-CO transformation by using the carbon nanotubes-supported PCN-222(Fe) nanoparticles composite

Molecular complexes with active metal centers exhibit high activity and selectivity for electrochemical CO2 reduction reaction (CO2RR), which represents a promising method for transforming greenhouse gas into valuable chemicals and feedstock. Using metal–organic frameworks (MOFs) to load the active molecular complexes then employing the combination with the carbonic conducting material may exhibit a beneficial effect for CO2RR. Herein, we obtained a composite catalyst named PCN-222(Fe)/CNTs, which was in situ synthesized through the solvothermal method that loads iron porphyrin-centered PCN-222(Fe) molecules onto CNTs. The catalyst PCN-222(Fe)/CNTs exhibits excellent electrocatalytic performance for CO2RR with a FECO of 95.5% (m(Fe-TCPP):m(CNTs) = 1:30, written as PCN-222(Fe)/CNTs-30) and an overpotential (η) of 494 mV. In addition, the turnover frequency (TOF) is high as 448.76 h−1 (3.011 site−1 s−1) and the hydrogen evolution reaction (HER) is indistinctive. After long-term electrocatalysis of 10 h at −0.6 V vs. RHE, PCN-222(Fe)/CNTs-30 remained its high catalytic performance with average FECO = 90%. This work provides a solid foundation for further research in the high-efficiency transformation of CO2 to CO.Graphical abstract