Enhancing *CO and *N≡N Orbital Coupling via Tuned Mn d‐p Hybridization at MnO/Mn <sub>7</sub> C <sub>3</sub> Interfaces for Highly Selective Urea Electrosynthesis
Xin Ge, Jili Yuan, Hu Li, Liang Wang, Haibo Xie, Chengbin Liu
Abstract
Abstract Electrocatalytic CO 2 and N 2 co‐reduction to urea under ambient conditions offers a promising route toward sustainable urea production. However, achieving efficient activation and selective C─N coupling of both carbon‐ and nitrogen‐containing intermediates remains a formidable challenge. Herein, a MnO/Mn 7 C 3 nano‐heterostructure electrocatalyst is reported featuring interfacial Mn‐atoms with optimized 3d‐2p orbital hybridization to promote C─N coupling kinetics. By fine‐tuning the MnO‐to‐Mn 7 C 3 ratio, interfacial electron transfer from Mn 7 C 3 to MnO is regulated, maximizing the density of electronically active interfacial Mn‐sites. The optimized catalyst delivers a record‐high Faradaic efficiency of 70.2 ± 4.5 % and the urea yield of 233.5 ± 12.8 µg h −1 mg cat −1 at –0.5 V versus RHE, outperforming the previously‐reported‐electrocatalysts. Mechanistic studies reveal that the interfacial Mn 3d‐2p hybrid orbitals are favorably alignment with the π* orbitals of *CO and *N 2 , facilitating the formation of key *NCON intermediate with a partially occupied d–π orbital in the β‐spin state. Moreover, it is also demonstrated that the newly formed π orbital in *NCON aligns well with the Mn α‐spin 3d–2p orbitals, enabling partial orbital occupation that promotes facile hydrogenation. This work offers valuable insights into the rational design of electrocatalysts for efficient urea synthesis.