Enhanced CO ₂ Activation Through Spin States Engineering Boosting Urea Electrosynthesis From Co‐Reduction of CO ₂ and NO ₂ ⁻

Abstract

ABSTRACT Electrocatalytic urea synthesis through co‐reduction of CO 2 and NO 3 − /NO 2 − has been considered as a sustainable alternative for urea production. However, the challenge for inert CO 2 activation results in inefficient C‐containing species coverage, leading to low urea yield and dominant NH 3 production. Herein, we design a Cu‐Mn dual‐site catalyst by co‐embedding CuO x clusters and single‐atomic Mn sites on C 3 N 4 ‐coated carbon nanotubes (CuO x /Mn 1 ‐C 3 N 4 @CNT) for urea electrosynthesis through co‐reduction of CO 2 and NO 2 − . Experimental and theoretical results show that the electron transfer from CuO x clusters to single‐atomic Mn sites induces Mn 3d electron delocalization and further spin configuration transformation from low spin states to high spin states. The electronic states regulation improves electron‐donation ability of Mn sites to substrates and enables the enhanced CO 2 activation and C‐containing intermediates adsorption behavior, facilitating coupling with N‐intermediates. Consequently, the CuO x /Mn 1 ‐C 3 N 4 @CNT catalyst achieves 60.2% urea Faradaic efficiency at −0.4 V (vs. RHE), 100% carbon selectivity over a record‐wide potential range of 300 mV, and exceptional 336 h cycling stability with 202.4 mg urea production. This work reveals a clear mechanism for performance enhancement through electronic interactions of dual sites and provides a dual‐substrate conversion catalyst design strategy.