X.H. Wu ‡ *, J.J. Lin ‡, Y.Y. Zhang, R.C. Sun and Z.-S. Wu *

ACS Catalysis, 2025, accepted.

Nitrate electroreduction reaction (NO3-RR) represents a sustainable strategy for the production of high value-added platform chemical ammonia. However, the  absence of appropriate tandem electrocatalysts for the NO3-RR limits further development. Here we report a ternary FeNiCu layered double-hydroxide (LDH) nanosheet catalyst with multiple active sites grown on nickel foam (FeNiCu-LDH/NF) for efficient electroreduction of nitrate sources into ammonia. The FeNiCu-LDH/NF shows a high activity for the NO3-RR resulting in a low potential of 0.328 and 0.247 V vs. RHE to attain a current density of 10 and 100 mA cm-2, respectively. Both experimental observations and theoretical analyses demonstrate that the multiple active sites of FeNiCu-LDH/NF efficiently catalyze NO3-RR in tandem. The Cu top sites boost the reduction of *NO3 to *NO2, and the Fe-Ni bridge site promotes the reduction of *NO2 to *N, then the Fe-Cu-Ni hollow site accelerates the hydrogenation of *N to *NH3. Moreover, nitrate electroreduction reaction coupled with glucose electrooxidation reaction can synergistically produce ammonia at the cathode and glucaric acid at the anode in a low potential. Meanwhile, ammonia is successfully collected through the air stripping method  .