Well‐Defined Single‐Atom Cobalt Catalyst for Electrocatalytic Flue Gas CO 2 Reduction

Single‐atom Co catalyst Co‐Tpy‐C with well‐defined sites is synthesized by pyrolysis of a Co terpyridine (Tpy) organometallic complex. The Co‐Tpy‐C catalyst exhibits excellent activity for the electrochemical CO 2 reduction reaction in aqueous electrolyte, with CO faradaic efficiency (FE) of over 95% from −0.7 to −1.0 V (vs RHE). By comparison, catalysts without Co or Tpy ligand added do not show any high CO FE. When simulated flue gas with 15% of CO 2 is used as the source of CO 2 , CO FE is kept at 90.1% at −0.5 V versus RHE. During gas phase flow electrolysis using simulated flue gas, the CO partial current density is further increased to 86.4 mA cm −2 and CO FE reached >90% at the cell voltage of 3.4 V. Experiments and density functional theory calculations indicate that uniform single‐atom Co–N 4 sites mainly contribute to the high activity for CO 2 reduction.