Boosting * NOH Intermediate Generation Kinetics for Nitrate Synthesis: Insights From Photo‐Assisted Electrocatalytic Nitrogen Oxidation

ABSTRACT The electrocatalytic nitrogen oxidation reaction (eNOR) offers a sustainable route for nitrate (NO 3 ‒ ) synthesis, yet its practical application is limited by sluggish intermediate formation kinetics. Although •OH generated during water oxidation can promote the formation of the key * NOH intermediate, the cooperative mechanism between •OH and catalytic sites remains insufficiently understood. Herein, a spin‐state modulation strategy is proposed to enhance * NOH generation under simulated solar irradiation, thereby markedly improving the NO 3 ‒ yield and Faradaic efficiency (FE) of the eNOR. A heterojunction catalyst consisting of CoMo‐based layered double hydroxide nanosheets grown in situ on Ti 3 C 2 T x MXene (CoMo‐LDH@Ti 3 C 2 T x ) was developed to enable light‐assisted eNOR. The incorporation of Mo into Co‐LDH, together with the built‐in electric field of the heterojunction, enhances Mo–Co orbital hybridization and induces a spin‐state transition of Co 3+ centers from t 2g 6 e g 0 to t 2g 4 e g 2 configuration. This electronic regulation strengthens N 2 activation and accelerates * NOH formation via the cooperative involvement of two •OH radicals under illumination, thereby significantly boosting eNOR kinetics. Consequently, CoMo‐LDH@Ti 3 C 2 T x delivers NO 3 ‒ yield of 198.55 µg h −1 mg cat. −1 and FE of 46.22% under solar light, outperforming dark conditions and state‐of‐the‐art catalysts. These findings underscore the critical roles of spin‐state engineering and radical synergy in advancing sustainable nitrate production.