Pd‐Doped Co3O4 Nanoarray for Efficient Eight‐Electron Nitrate Electrocatalytic Reduction to Ammonia Synthesis

Abstract Ammonia (NH 3 ) is an indispensable feedstock for fertilizer production and one of the most ideal green hydrogen rich fuel. Electrochemical nitrate (NO 3 − ) reduction reaction (NO 3 − RR) is being explored as a promising strategy for green to synthesize industrial‐scale NH 3 , which has nonetheless involved complex multi‐reaction process. This work presents a Pd‐doped Co 3 O 4 nanoarray on titanium mesh (Pd‐Co 3 O 4 /TM) electrode for highly efficient and selective electrocatalytic NO 3 − RR to NH 3 at low onset potential. The well‐designed Pd‐Co 3 O 4 /TM delivers a large NH 3 yield of 745.6 µmol h −1 cm −2 and an extremely high Faradaic efficiency (FE) of 98.7% at −0.3 V with strong stability. These calculations further indicate that the doping Co 3 O 4 with Pd improves the adsorption characteristic of Pd‐Co 3 O 4 and optimizes the free energies for intermediates, thereby facilitating the kinetics of the reaction. Furthermore, assembling this catalyst in a Zn‐NO 3 − battery realizes a power density of 3.9 mW cm −2 and an excellent FE of 98.8% for NH 3 .