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

Ammonia (NH3) is an indispensable feedstock for fertilizer production and one of the most ideal green hydrogen rich fuel. Electrochemical nitrate (NO3-) reduction reaction (NO3-RR) is being explored as a promising strategy for green to synthesize industrial-scale NH3, which has nonetheless involved complex multi-reaction process. This work presents a Pd-doped Co3O4 nanoarray on titanium mesh (Pd-Co3O4/TM) electrode for highly efficient and selective electrocatalytic NO3-RR to NH3 at low onset potential. The well-designed Pd-Co3O4/TM delivers a large NH3 yield of 745.6 mu mol 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 Co3O4 with Pd improves the adsorption characteristic of Pd-Co3O4 and optimizes the free energies for intermediates, thereby facilitating the kinetics of the reaction. Furthermore, assembling this catalyst in a Zn-NO3- battery realizes a power density of 3.9 mW cm(-2) and an excellent FE of 98.8% for NH3.

Automated summary

This work presents a Pd-doped Co3O4 nanoarray on titanium mesh (Pd-Co3O4/TM) electrode for efficient electrocatalytic NO3-RR to NH3 production. The catalyst exhibits a large NH3 yield of 745.6 μmol h(-1) cm(-2) and a high Faradaic efficiency of 98.7% at -0.3 V with strong stability. The doping of Co3O4 with Pd improves the adsorption characteristics and optimizes the free energies for intermediates, enhancing the reaction kinetics. Additionally, the catalyst assembled in a Zn-NO3- battery achieves a power density of 3.9 mW cm(-2) and an excellent FE of 98.8% for NH3.