Preparation And Electrocatalytic Study Of Fe And Zn Monatomic Materials Supported By Nanometer Carbon Materials

Monoatomic catalysts?SACs?are regarded as the most promising catalysts for CO₂RR and ORR because of their complete atomic utilization rate and special coordination structure.However,there are many factors that affect the efficiency of single-atom catalysts.The doping of carbon supports and heterogeneous atoms of catalysts plays a crucial role in catalysis.The carbon nano-onion?ZnN/CNO?material with zinc single atoms supported on high curvature was prepared by high-temperature pyrolysis.The transmission,spherical aberration electron microscopy and X-ray absorption spectrum proved that Zn exists in the form of single atoms.The X-ray absorption spectrum proves that the Zn-N₄ coordination structure has an electrochemical reduction activity and selectivity to carbon dioxide of up to 97%,and maintains 90%activity after 20 hours of durability.Experiments and density functional theory?DFT?revealed that the high curvature CNO substrate can reduce the thickness of the electric double layer,which in turn makes the COOH*intermediate bond stronger and promotes the conversion of CO₂RR to CO.The N and S co-doped iron single atoms supported on carbon nanotubes?FeN/FeS-CNT?catalyst materials were prepared by pyrolysis at high temperature,and Fe N/FeS-CNT was proved by X-ray absorption near-edge spectroscopy?XANES?The valence state of the Fe atom in is+2 valence.Extended X-ray absorption fine structure spectroscopy?EXAFS?proves that N and S atoms form Fe-N and Fe-S bonds with Fe atoms,and the initial potential is obtained by testing the oxygen reduction reaction And half-wave potentials are 1.1 V and0.91 V,respectively,higher than the activity of Pt/C 0.87 V vs.RHE.Combined with electrochemical performance and characterization,it is proved that Fe-N and Fe-S are catalytic active sites of oxygen reduction reaction,indicating that the incorporation of heterogeneous atoms N and S can promote the oxygen reduction reaction.These studies provide a good method for rational design of electrocatalysts with excellent performance and clear structure.