Saturated Coordination LuN₆ Defect Sites for Highly Efficient Electroreduction of CO₂

Abstract

Metal single-atom and internal structural defects typically coexist in M-N-C materials obtained through the existing basic pyrolysis processes. Identifying a correlation between them to understand the structure-activity relationship and achieve efficient catalytic performance is important, particularly for the rare-earth (RE) elements with rich electron orbitals and strong coordination capabilities. Herein, a novel single-atom catalyst based on the RE element lutetium is successfully synthesized on a N-C support. Structural and simulation analyses demonstrate that the formation of a LuN₆ structural site with an individual defect because of pyrolysis is thermodynamically favorable in Lu-N-C. Using KHCO₃ -based electrolytes facilitates the fall of the K⁺ cations into the defective sites of Lu-N-C, thus enabling improved CO₂ capture and activation, which increases the catalyst conductivity for Lu-N-C. In this study, the catalyst exhibits a Faradaic efficiency of 95.1% for CO at a current density of 18.2 mA cm^-2 during carbon dioxide reduction reaction. This study thus provides new insights into understanding RE-N-C materials for energy utilization.