Atomic Precision CoCu Heterodimers with Pseudo‐D _3h Symmetry Enable Tandem Nitrate Reduction

The electrochemical reduction of nitrate (eNO₃RR) to ammonia (NH₃) is an efficient method for mitigating nitrate (NO₃ ^-) pollutant while offering sustainable NH₃ generation under ambient environments. However, optimizing NO₃ ^- adsorption on catalytic surfaces and promoting adsorbed hydrogen formation remain challenging. Herein, we introduce pulsed laser irradiation in liquid for the first time to design a metal-metal-ligand-coordinated CoCu heterodimer catalyst with a pseudo-D_3h symmetry anchored on nitrogen-doped graphene oxide (CoCu-HeD/NGO), enabling a tandem catalytic effect for the eNO₃RR. The catalyst reaches a remarkable Faradaic efficiency of 91% at -0.4 V vs. RHE and a high NH₃ production rate of 25 mg h^-1 cm^-2 at -0.5 V vs. RHE. Combined theoretical and in situ spectroelectrochemical analyses reveal that the synergistic interaction among Co and Cu dual sites enhances NO₃ ^- adsorption, weakens N─O bonds, and facilitates the establishment of Langmuir-Hinshelwood-type hydrogenation intermediates, steering the tandem reaction pathway toward selective NH₃ formation. Furthermore, a Zn-nitrate battery with a CoCu-HeD/NGO cathode integrates energy generation and NH₃ synthesis with environmental remediation, delivering 5.26 mW cm^-2 power density and stable discharge performance. Practical NH₃ production is verified via Ar stripping-acid-trapping methods. This work establishes a new paradigm for the rational design of site-selective electrocatalysts for hybrid energy-to-chemical platforms.