Design of bifunctional single-atom catalysts NiSA/ZIF-300 for CO_(2) conversion by ligand regulation strategy

Carbon-supported noble-metal-free single-atom catalysts(SACs)have aroused widespread interest due to their green chemistry aspects and excellent performances.Herein,we propose a“ligand regulation strategy”and achieve the successful fabrication of bifunctional SAC/MOF(MOF=metal-organic framework)nanocomposite(abbreviated NiSA/ZIF-300;ZIF=ZIF-8)with exceptional catalytic performance and robustness.The designed NiSA/ZIF-300 has a planar interfacial structure with the Ni atom,involving one S and three N atoms bonded to Ni(Ⅱ),fabricated by controllable pyrolysis of volatile Ni-S fragments.For CO_(2) cycloaddition to styrene epoxide,NiSA/ZIF-300 exhibits ultrahigh activity(turnover number(TON)=1.18×105;turnover frequency(TOF)=9830 molSC·mol_(Ni)^(-1)·h^(-1);SC=styrene carbonate)and durability at 70℃ under 1 atm CO_(2) pressure,which is much superior to Ni complex/ZIF,NiNP/ZIF-300,and most reported catalysts.This study offers a simple method of bifunctional SAC/MOF nanocomposite fabrication and usage,and provides guidance for the precise design of additional original SACs with unique catalytic properties.