Nitrogen-bridged Fe-Cu Atomic Pair Sites for Efficient Electrochemical Ammonia Production and Electricity Generation with Zn-NO2 Batteries.

Abstract

The development of environmentally sustainable and highly efficient technologies for ammonia production is crucial for the future advancement of carbon-neutral energy systems. The nitrite reduction reaction (NO2 RR) for generating NH3 is a promising alternative to the low-efficiency nitrogen reduction reaction (NRR), owing to the low N=O bond energy and high solubility of nitrite. In this study, we designed a highly efficient dual-atom catalyst with Fe-Cu atomic pair sites (termed FeCu DAC), and the as-developed FeCu DAC was able to afford a remarkable NH3 yield of 24,526 μg h-1 mgcat. -1 at -0.6 V, with a Faradaic Efficiency (FE) for NH3 production of 99.88 %. The FeCu DAC also exhibited exceptional catalytic activity and selectivity in a Zn-NO2 battery, achieving a record-breaking power density of 23.6 mW cm-2 and maximum NH3 FE of 92.23 % at 20 mA cm-2 . Theoretical simulation demonstrated that the incorporation of the Cu atom changed the energy of the Fe 3d orbital and lowered the energy barrier, thereby accelerating the NO2 RR. This study not only demonstrates the potential of galvanic nitrite-based cells for expanding the field of Zn-based batteries, but also provides fundamental interpretation for the synergistic effect in highly dispersed dual-atom catalysts.