Spontaneous Metal‐Chelation Strategy for Highly Dense Ni Single‐Atom Catalysts with Asymmetric Coordination in CO<sub>2</sub> Electroreduction
Jae Hak Kim, Jaehyun Kim, Joonhee Ma, Jin Hyuk Cho, Jae‐Min Jeong, Soshi Iimura, Ho Won Jang, Soo Young Kim
Abstract
Abstract Developing metal–nitrogen‐doped carbon single‐atom catalysts (M–NC SACs) with high loadings for the electrochemical CO 2 reduction reaction (eCO 2 RR) remains challenging owing to the risk of metal aggregation. Herein, the study presents a facile strategy for synthesizing M–NC SACs using metal‐chelating ligands, eliminating the need for additional processing steps. Specifically, using ethylenediaminetetraacetic acid as a strong metal‐chelating ligand, the formation of Ni nanoparticles is effectively prevented and a high loading of ≈2.7 wt.% is achieved, leading to the development of high‐loading Ni SACs. The resulting catalysts exhibit a high CO faradaic efficiency (FE CO ) of 96.6% and CO partial current density of −120.2 mA cm −2 and retain a FE CO over 90% in a broad potential range of −0.4 to −0.9 V versus the reversible hydrogen electrode. Furthermore, theoretical calculations indicate that the asymmetric Ni–N 3 C 1 local coordination structure within the catalyst reveals an optimal balance between *COOH formation and *CO desorption, which enhances the activity for eCO 2 RR to CO. This study offers an efficient strategy to suppress metal nanoparticle formation while simultaneously improving the metal loading in M–NC SACs.