Creation of intrinsic defects on ZIF-8 particles to facilitate electrochemical reduction of CO2 over Fe single-atom catalyst

The fabrication of various defects on the surface of metal single-atom catalysts can improve their electrochemical CO2 reduction reaction (CO2RR) ability, and the current mainstream research focuses on the defect modification of heteroatom doping, while there are fewer studies on intrinsic defects on carbon substrates. Herein, a series of catalysts with both Fe-N4 sites and intrinsic defects were synthesized on the ZIF-8 surface by pyrolytic etching at a suitable temperature under ammonia atmosphere. Electrochemical tests in an H-cell showed that the catalyst achieved CO Faradaic efficiency (FECO) of 96.9 % and CO partial current density (JCO) of 9.088 mA cm−2 at −0.6 V. Through further studies, we introduced a "585" ring structure to describe these intrinsic defects and found that these intrinsic defects on the carbon-based surface can act as active sites to promote CO2RR along with the Fe-N4 sites. This work provides a reference for the study of intrinsic defect-modified single atomic materials.