Dynamic CoOOH@Co Reconstruction Activates Laser‐Decorated Pd Sites for High‐Selectivity Nitrate‐to‐Ammonia Electrocatalysis and Zn–Nitrate Batteries

ABSTRACT In this study, we introduce a rational design of pulsed laser irradiation in liquids ‐synthesized Pd nanoparticle‐decorated Co nanodendrites (Pd/Co NDs), exhibiting high activity and selectivity toward the nitrate reduction reaction (NO 3 RR). The optimized Pd/Co ND‐3 electrocatalyst achieves a maximum Faradaic efficiency (FE) of 92.35% at −0.1 V vs. RHE and a maximum NH 3 yield rate of 9.03 mg h −1 cm −2 at −0.4 V vs RHE during NO 3 RR. Combined in situ and ex situ spectroscopic analyses reveal dynamic surface reconstruction processes occurring under reaction conditions. Specifically, the Pd/Co NDs undergo structural transformation into a Pd/CoOOH@Co structure during NO 3 RR, where the synergistic interaction within the reconstructed Pd/CoOOH@Co NDs remarkably enhances catalytic performance, as further supported by theoretical calculations. Furthermore, a Zn‐NO 3 − battery using Pd/Co NDs as the cathode achieves an open‐circuit voltage of 1.506 V and the cathodic NO 3 RR FE of 68.78% at a current density of 4 mA cm −2 , with long‐term stability over 500 h. This study highlights the importance of surface reconstructions in the Pd/CoOOH@Co ND electrocatalysis for NO 3 RR and the performance of the Zn‐NO 3 − battery, providing valuable insights for designing advanced electrocatalysts aimed at sustainable NH 3 synthesis from NO 3 − pollutants.